Saturday, December 27, 2008

Early plans for a lunar mission

"Design of the British Interplanetary Society's BIS Spaceship began in 1937 and was published in January and July 1939. The purpose of the exercise was to prove that a manned lunar expedition could be designed using existing powder rocket technology. The design was reformulated in 1947 based on information on German advances with liquid propellant rockets.

Available British rocket technology then consisting only of powder rockets, the booster consisted of 2,490 such rockets, which were shed as soon as they were exhausted. Thus a kind of 'infinite' staging was used to compensate for the very low specific impulse of the motors. The hexagonal booster was 6 meters in diameter and 32 meters long, with a lift-off mass of 1112 metric tons. Launch was from a flooded caisson in a high-altitude lake near the equator. The one metric ton spacecraft delivered a crew of three to the lunar surface, landing on gear very similar to those used for the Apollo Lunar Module sixty years later. Following re-entry in the earth's atmosphere, a parachute was used for final descent. Oddly, heating during ascent through the atmosphere was seen as a real problem, while re-entry on return was considered trivial ("accomplished in easy stages" via aerobraking). Therefore a jettisonable ceramic shield protected the spacecraft from heating expected to reach 1500 deg C during ascent, while no heat shield was considered necessary for return.

J Happian Edwards led the design team, which included H Bramhill (draftsman), Arthur C Clarke (astronomer), A V Cleaver (aircraft engineer), M K Hanson (mathematician), Arthur Hanser (chemist), S Klemantski (biologist), HE Ross (electrical engineer), and R A Smith (turbine engineer)."

The ideas here are essentially sound, if highly optimistic. The spacecraft mass would have to be probably an order of magnitude more massive, and the capsule would need heavy shielding for reentry rather than exit of the the atmosphere. Further, it is unlikely that people could survive reentry without a lifting body entry craft, because a direct entry from the moon results in huge G forces like 15 or more Gs.

Tuesday, December 23, 2008

Sprint ABM Silo

This drawing of a Sprint Silo was located online. It is not known at this time if the details are accurate or not, probably this is an artistic interpretation. What can be seen is a piston or sabot of sorts, probably used to eject the Sprint at high accelerations. Note the double walled, lenticular cover with what seems like a hollow space. Is this to harden the rocket against a nuclear attack? The dome is obviously the strongest shape to resist pressure, though a cone would probably be better at deflecting heavy impulse impacts. Why hollow? Would this space hold water or other materials for radiation shielding?

** Update **

I now have the source and information about this image. This is an accurate Sprint Silo:

"In the 1970’s, the Martin Marietta Corporation (now Lockheed Martin) in Orlando, Florida, built what is still today one of the most incredible guided missiles ever to fly. The Sprint was a part of the only anti-ballistic missile (ABM) system that the United States ever deployed. Complementing the long-range Spartan interceptor, which was intended to destroy incoming nuclear warheads before they re-entered the atmosphere, Sprint was a short-range screamer with literally split-second reactions. It could intercept any warheads that got past Spartan when they were only seconds from their targets. Ejected from an underground silo by a hot gas generator, the two-stage Sprint accelerated so fast that it would pass a .50-calibre bullet, if fired at the same time, within a second. Atmospheric friction made the outside skin of the second stage hotter than the inside of the rocket motor. It was protected by a thick ablative layer that actually boiled away, carrying the heat with it. Sprint was tested successfully many times at White Sands Missile Range, New Mexico and at the Kwajalein Missile Range in the Pacific. It was beyond-state-of-the-art technology for its day.

This image shows Sprint in its silo. The missile sits on the eject piston, which in turn rests on a ring of springs to cushion the missile from ground shocks. When the gas generator under the piston fires, the piston shoots up the launch tube (stopping when it hits the piston arrestors at the tube mouth) and the Sprint continues out of the cell, literally blasting through the frangible fiberglass, foam and rubber domed cell closure. Tan “wedges” at the missile’s midsection near the second stage fins guide it out the tube. The cutaway shroud near the top of the missile is the “foam sock,” an insulating blanket around the guidance section and warhead that keeps the components at operating temperature at all times."


Friday, December 19, 2008

Aerotech opens new store:

Aerotech just launched this web page to sell a small number of mid power items at a very low price. They claim this is to 1.) introduce more people to the hobby, and 2.) help us in these hard times. Among other items, they will be selling E15W and E30T motors will be for $18.90 per 3-pack. This is indeed a very good price. If you spend less than $100, you have shipping. More, and shipping is free. 18mm reload cases are going for $30 also. I almost wanted to get one, but will resist. Give the page a visit some time, see what you think.

I personally dont get why they cant sell the 24mm cases and reloads as well. I suspect they dont want to undercut retailers all too much.

Friday, December 12, 2008

Some new books

These books are part of the latest Amazon order. Some of them were only $5 shipped... compared to the stamped prices of 15, 20, 25, or more each. Great deals! The space shuttle book is hardcover, and the sequel to one already in our library. The Praxis books are very nice also, I chose Russian topics because that is an area that is not covered very well by other sources. A few more books will arrive shortly.

Sunday, December 7, 2008

More sprint ABM images

You may have noticed that my icon changed from Cadavre, to the Sprint missile. I may change back at some point, but I wanted to lend some support to my rocketry projects which have been revived considerably during the past year, when compared to the relative lull since 2004. Cadavre may return, but for now it is rocketry stuff. In the spirit of celebrating the new icon, please find below additional images of the Sprint rocket. I have added some basic information so that everyone can be on the same page. Check the link below for my first sprint post.

Sprint post from the archive.

Sprint info:

"It was a two stage rocket with a 1 KT Neutron bomb to take out the IRVs via explosive force and neutron flux. It worked up to 100,000 feet, and could hit more than mach 10. It was about 7,700 lbs, but took off with 650,000 lbs of thrust. Acceleration was 100 Gs." -R2K

Wednesday, December 3, 2008

Three new rockets

These are the latest three rockets from art applewhite, and probably my last build for this year. The shiny metallic one is a 29mm cone rocket. It breaks apart for recovery. Two helix style rockets were also built. I need to make a special launch pad for them: they launch from a 1 inch long rod, and need a very stable pad that is just at ground level. One is 18mm and the other is 24mm.

Here is a video of a HUGE monocopter rocket.

Sunday, November 23, 2008

Orion (Ares) LES rocket test

These are some recently uploaded videos of the LES (emergency escape rocket) designed to pull the manned Orion capsule (with 4 men) off of the Areas I rocket in the event of an abort. I think this will be used from the pad, or low speed flight (maybe to 100 KM or so). This is very high thrust for a short period of time, it has to pull a large object clear. The lower bound of the impulse is set by the need to carry the men high enough to give the recovery system time to act all the same. I expect several thousand feet is the target. G forced experienced on ejection could hit or pass 10 Gs. This is within limits, but probably pretty painful and dangerous all the same. As pilots know, ejection is a last resort. This will probably still be far safer and more gentle than a jet ejection. There is a Praxis (large line of great space books) book coming out on emergency and abort systems for space flight. But not yet, some day it will be out. If anyone wants to buy it and donate to me, leave a comment.

This is how it is expected to work. Please comment if youtube videos are not working for you. From time to time, I seem to have problems with them on my own pages. Is that the page? Or the video? Or my computer? Hard to figure out.

Here are some specs on the system:

"On ignition, the abort motor fired for 5.5 seconds. The high impulse motor was developed to expend the majority of its propellant in the first three seconds, delivering the half million pounds of thrust needed to pull the capsule away from its launch vehicle in an emergency abort.

While similar to the Apollo Program's launch abort motor, Orion's abort motor incorporates today's technology into a more robust design. The launch abort motor uses a composite case and an exhaust turn-flow technology instead of a tower, which results in weight savings, improved performance and improved success in crew survival during an abort. Instead of the rocket plume exiting a rear nozzle, the manifold is placed at the forward end of the motor. The rocket thrust enters the manifold and is turned 155 degrees and forced out the four nozzles, creating a forward-pulling force."


Sunday, November 16, 2008

Extra-solar planets!

I cant wait for NGST to be turned on these things. And Kepler! And now we might be getting a dark energy - dark matter mission around 2015 also. Unmanned exploration has been a huge success, for centuries to come we will be remembered probably for many bad things, but also for a few great things.

Tuesday, November 11, 2008

Phobos Grunt

I wanted to post about this, my new favorite space project. But at the same time, I have a short angry rant.

The Russians (!) are planning to launch a very impressive, very daring and risky space project to land a craft on the larger (but still very small) moon of Mars; Phobos. Phobos is about 20 km on a side (but hardly regular in shape) and orbits Mars at around 10,000 km.

From the wiki page:

"Immediately after the touchdown, the lander will load a soil sample into a return rocket. In case of a breakdown of communications with mission control, it can enter an emergency mode to collect samples and still send them home in the return rocket. Normal collection could last from two days to a week. The robotic arm can collect rocks up to about half an inch in diameter. It ends in a pipe-shaped tool that splits to form a claw. This encloses a piston that will push the soil sample into an artillery-shell-shaped container. A light-sensitive photo-diode in the claw will help scientists confirm that the device did scoop material. They hope also to see images of trenches the claw leaves on the surface. The manipulator should perform 15 to 20 scoops yielding a total of three to five and a half ounces of soil.[3][4]

The return rocket will sit atop the spacecraft, and will need to rise at 22 mph to escape Phobos' gravity. To protect experiments remaining on the lander, springs will vault the rocket to a safe height, at which its engines will fire and begin maneuvers for the eventual trip to Earth.[3]

The lander's experiments will continue in-situ on Phobos' surface for a year. To conserve power, mission control will turn these on and off in a precise sequence. The robotic arm will place more samples in a chamber that will heat it and analyze its spectrum. This analysis might determine the presence of easily vaporized substances, such as water.[3]

The landing site that has been chosen is a region from 5°S to 5°N, 230° to 235°W."

This is a very risky project, and a historical first. The odds of success are, and I will be depressing, quite low. 50/50 would not be out of the question. But consider the cost - only $65 million! I am saddened that nasa spent about $500 million (including launch and operation mind you) on the Phoenix, and it just lasted one season. In a perfect world all projects would get funded, but I would hate to push back our Europa explorer even one year to pay for Phoenix. I am very proud of the Russians, the Chinese, the ESA, and India as they take a larger part in space exploration. As the government consistently under-funds NASA, we need to diversify and rely on others who continue to dream about space exploration, even if they live in other countries.

And this brings me to the rant: on the Phobos Grunt spacecraft there is a small capsule containing living organisms to test how they last in space: they will be returned with the Phobos sample capsule. This project is from the Planetary Society, a great private organization that helps further the cause of space exploration. You may remember that they recently launched a solar sail into space aboard an old ICBM. This was a very nice project. But here we have a very stupid, irresponsible, unnecessary, and scientifically pointless project. First of all the dangers: we are sending spores and other living samples on a course that could cause them to crash on mars, Phobos, or earth contaminating the Phobos samples (bad) or Mars (worse). Risking contamination at a time when the search for life on other planets or moons is the biggest problem. But also, this is a stupid project because the capsule hardly tests panspermia in a scientific way. The organisms will only space soak for a few years at most. That is not the thousands or millions of years likely in a panspermia mechanism. Also, they are protected and sealed in a metal case! Not embedded in a porous rock material. Anyway, the worst part is that sending the sample to Phobos is a waste of energy: every condition and form of adversity that is found at Mars orbit can be recreated here in Earth orbit or ON EARTH IN A LAB for less money and no risk. The radiation, the vacuum, the cold... we can make them all.

But dont let my anger about this distraction of an experiment ruin Phobos-Grunt for you, it wont for me. The Russians are taking a big bite here, and I hope they can get the project done and working on time. I cant stress how much the Russians have done for planetary exploration on a very limited budged in the past 50 years. Here are some links for more information:

Air+Space Article
PDF on the project
Russian Planetary Exploration

Friday, November 7, 2008

NY Rocketry Field

This is the field that I attend when flying in New York. This is located about 90 minutes north west of the city, in the Hudson valley west of Bear Mt. Note that these images just show 1/4th of the farm. A perfect place for rocketry. Probably on the order of 1000+ Acres.

Sunday, November 2, 2008

Last launch for the year

This was a great launch today: conditions were good, wind was acceptable, and most flights were successful. There were a few K flights, and one skidmark. One large rocket was reported to have gone past 10,000 feet. I flew a 24mm hourglass rocket on a D15T-4, the Graduator on an E16W-4 (great low slow flight) and a G64W-7, and finally the SNP on the requisite F12J-3. All four rockets flew fine, and I was able to recover them all. Why only 4 flights? Well the pictures below tell the story of what I did with my last hour at the field:

The SNP had a great flight as usual on the F12, it just doesnt get better than this rocket and this motor for a mid power flight. Recovery was going very well, close to the pad. Sadly, it fell directly into the center of the large stream that divides the field. This is a small target and a minor risk, but I was unlucky and hit it dead on. Because this rocket has a large plastic payload tube, it will float indefinitely. There is only one problem: I was unable to reach the rocket. This stream is the size of a small river, and the rocket just would not move from the dead center. At this point, keep in mind that while the rocket was already soaked and probably no good, it contained a 24/40 motor case that costs twice as much as the rocket. I needed to get this case back.
The rocket slowly drifted downstream for about a mile. At this point, I gave up trying and went back to the launch line to pack up. I then drove down the farm parallel to the stream for about a mile or so. I found the rocket floating again. On a whim, I continued to drive to see if there ever would be a snag or eddy or any hope. About 1000 feet up, I found a huge dam made from a fallen tree and much flotsam. A metal drum, a very old rocket, lots of bottles, and a pallet were some of the items I found there:I carefully walked out on this mat of flotsam and waited for the rocket. I should also share that this was hardly a stable platform: it was mostly floating in the water that was 5 or more feet deep and moving rapidly. Further, this water was not a clean stream but farm runoff containing all kinds of fertilizer and pesticides. This was a dangerous situation because falling off would at least mean a very nasty dunking in cold water. But it could have been worse, falling into the center of the dam potentially could kill a person if they could not get back up or out.

Anyway the rocket came and was within reach. I grabbed a long stick and was able to pull it out of the water before it was sucked under the dam (and possibly lost forever). The rocket was waterlogged to say the least, and I threw it out (not wanting to reuse it or deal with cleaning it). The motor case, at $45, is back with me safe and sound. Obviously this was more of an adventure than expected. For the next post I prepared some images of the farm so you can get an idea of what a nice field this is for flying. I am looking forward to next year, and am glad I found this club near me. Let me leave you with a very crappy video of the rocket floating in the stream:

Wednesday, October 29, 2008

Testing a hybrid motor with a spike nozzle.

This is a great project. The hybrid motor uses a solid fuel and a gaseous or liquid oxidizer. Here the fuel is a clear acrylic tube that lets you see inside the chamber. Note how bright it is: the flame that comes out of a motor is often bright, but inside there must be far more radiation.

The spike nozzle, aerospike, uses atmospheric pressure and can help maintain high efficiency. Bell nozzles can only be built for a certain fairly small pressure range (altitude) and then they lose efficiency outside of it.

Thursday, October 23, 2008

100th Post

This is a very nice video. It is generally not good practice to fly into or among clouds. The concern is that some aircraft could be inside them. But I personally love cloudbusting. And as this video shows: only by passing clouds can you really get a feel for how fast this (by no means a top performance flight) rocket was going. This was a massive M motor flight.

Sunday, October 19, 2008

Next cluster

This is a smaller rocket built from the same educators pack of simple kits. Of particular concern with this design is that there will be a large amount of pressure pushing the nose cones apart. This may result in a shred. Large amounts of glue should prevent this.

An interesting problem came up during work on this rocket: I have been using white glue as nose cone weight. I gave literally days for this glue to dry. After letting it dry, I finally put the cones into the rocket. After a few more days, I moved the rocket and found glue inside one tube! It turns out wet white glue is able to melt its way through dry glue like acidic alien blood. This was quite a shock, and called for some further work to bring the rocket back into shape. It can be salvaged, but for the future I must use epoxy.

This rocket will go well on motors from 1/2A up, even two D21s!

Friday, October 10, 2008

Custom kit

I recently was lucky enough to get a bunch of rockets and motors. An educator had an Estes bulk pack that he didnt want anymore. My plan is to build three rockets from the set: a 2 x 18mm cluster model, a stretched rocket for staging, and this 3 x 18mm cluster. The bag of motors is just a bunch of A8-3s... so that explains why the cluster designs, I need to find a way to burn those up in bulk.

This rocket has four body tubes, three nose cones, and six fins. To ensure stability, I added a few grams of white glue to the nose cone. The last step will be adding a launch lug; probably a 3/16ths or if not, a 1/4th. CA glue was used for reinforcements, and white glue for the initial assembly. The central tube will eject a small parachute, the outer two (nacelles) will eject a streamer each. Perhaps a short delay on the outer two then a longer delay on the center would be a nice dual deploy of sorts.

Sunday, October 5, 2008

Launch Report: 10-04

Again I apologize for the lack of images, I generally do not have the time or desire to take pictures during a launch because I am busy flying and enjoying flights! But rest assured, as soon as images and videos are posted to the web page of the local club, I will bring them here.

The launch this weekend was nearly perfect: weather was pretty warm, the sky was mostly clear, and the wind was low (but not quite as low as last time). As usual, many large rockets were present (this club is mostly a high power club), and two M motors were flown along with many K motors. Two large Skidmark motors were in this group, and they were as always the stars of the show. Very few flight failures occured, but the one level three attempt (the first of two Ms) did indeed fail because of a minor recovery mistake, and damage (I think) to the booster. The biggest failure was a ballistic recovery of a large rocket. It fell about 1000 feet behind the range (in horizon zero of the farm), and made a terrible crash sound.

I took my Graduator as a "large rocket" (boy how times have changed), along with the super nova payloader, and some small kits. The graduator flew on a F40T and G71R. The G71 was my first red flame motor, and it was indeed very nice. But the rocket ejection charge was weak (or early), and the parachute did not deploy. The rocket came in very hard with the body tube sticking into the ground. I had assumed that it was never going to fly again, but somehow the damage was very minor.

The SNP flew on a typically nice F12J, and cracked a fin on landing but that also will be easy to fix. Two 24mm art applewhite kits (the orange one and the hourglass one) flew on D motors. Both had strange, unstable flights. Both recovered just fine. Finally, the tiny 13mm paper rocket flew on an 1/2A3! It did very well, but the small parachute did not open: it needs to be modified.

All told, a great launch. Hopefully images to come. Previous launch reports will be updated as well with images.

Tuesday, September 30, 2008

Baikonur Cosmodrome

Some great images from the Baikonur Cosmodrome. As I said previously, Russian rockets are great and the Russian space program is very impressive despite being poorly funded and controlled by a highly corrupt government. Did anyone here know that the Russians flew two balloons in the atmosphere of Venus? Vega Program

Click here for more pictures and information.

Saturday, September 27, 2008

Small motor order

I just got a small set of RMS motor loads for my 29 and 24mm hardware. They are two G motors, one E, and 3 D motors. This order was placed at Hobby Linc; probably the cheapest source for small motors there is. I have a limited budget here, but I was seriously considering buying several G motors and just stocking up. They were only $8.69 each! One is a Redline (red flame) motor, and the other is an old school White Lighting item. The E16 (29mm) motor was also a great deal: only $5.79. It is just at the lower limit of what is needed for the Graduator. The D15 (24mm) has to be one of my favorite motors. A nice cute little thing that still has substantial power.

The next launch is next week!

Saturday, September 20, 2008

Aerospace video collection

These are all videos about aerospace related subjects. I would say that these are among the best videos out there right now. Project farside is a great example of the kind of rocket amateurs could be working on right now. This rocket was steps away from orbit, and a stage or two away from the moon.

Wednesday, September 17, 2008

Art Applewhite Free Kits

I have just finished my free kits from Art Applewhite. All of the larger kits remain to be built, but these 5 are all set to fly! They are all 13mm paper kits printed on 110 lbs cardstock. In a previous post, you were able to see my first attempt. The rest are all of a similar coniform design, save one. The most complex 13mm free kit, and the one saved for last for the sake of practice, is pictured here across the bottom. This kit is so much fun to build, taking about 1 hour given some basic practice. Notice the small (4 inch) parachute I made for this kit. It has a full action nose cone and shock cord, like any larger kit might. These are all real flying models, I will take them to a future launch.

Now on to the larger kits!

Saturday, September 13, 2008

METRA Launch

Documentation of launches is never that great, because I am always focused on the flying. Here is one pic of my table while setting up.

The weather was cloudy, with frequent clouds below 5,000 feet. But the wind was VERY low and for me, conditions were just about perfect. METRA launches as a large farm just west of Harriman park (Bear Mt.) which is about 60 miles north of New York City. When I say large, I mean on the order of 1,000 acres, perhaps more. And lots of sod for a mud free field, with soft landings. Lots of high power was launched today, including one really nice M motor. Lots of Skidmarks, and dual deployment flights. Only three (out of about 100) rockets seemed to fail badly. Sadly, one of them was mine. My brand new Big Daddy crashed on its first flight. I heard the ejection charge go off, but for some reason the nose cone did not eject. I wont get into the blame game, but the RSO did make me apply some tape to the nose shoulder, suggesting it was too lose. Could that have cost me $25? The problem isnt that he made the suggestion, the problem is that now I will never know. It is also possible that the motor was a bit loose and it let too much pressure leak out. Or maybe there wasnt enough BP in the motor, or it didnt burn well.

My four flights were: E11J on the SNP, D15T on the Big Daddy (lawn dart), an F52T on the Graduator, and then an F22J on the same Graduator. Other than the crash, the flights were great. The E11J ejection was very late, but the rocket did survive just fine. The two graduator flights were very nice. I previously had some concerns about the low thrust of the F22, but it was more than enough to loft the 1.6 lbs graduator. Both graduator recoveries were within 50 feet of me, due to the low wind and shockingly fast recovery on a 20 inch skyangle chute, that spun quite a bit. Both confused me... Recovery was faster than on a normal 18 incher, and should not spin at all due to the swivel mount on the skyangle.

Anyway, great fun. Some damage and some money down the drain, but well worth it. The M flight was very very nice. Dual recovery that landed in the flight line, bumping a car but not causing severe damage.

Saturday, September 6, 2008

Upcoming Launch

I will be attending a METRA (New York State Tripoli club) launch next weekend if weather holds out. A launch report will come soon after. The plan is to fly some of the larger motors mostly, as this will be a high power launch (the last one was a mid power notification launch). The 29mm reload case will be put to good use. Some 24mm motors will be used also, however, because I have a ton of them. So the plan is a bunch of F motors! F motors are really the sweet spot of mid power.

Check out this N motor video:

Wednesday, August 27, 2008


I think Russian rockets are pretty much the coolest of all. The N1 is possibly the most impressive, best looking rocket ever made. The inter-stage open truss design (common in communist rockets) might be a big part of it. Or could it be the conical shape of the thing? Anyway, there is something about the N1 that makes it look larger than any other, even the Saturn V and space shuttle. Larger and better, and maybe in some way what rockets should ideally have become. It looks somewhat slapped together also, like a borg spaceship... Note the spherical fuel tanks... these are less than optimum, but are just a very nice touch. The use of RP1 and LO2 is, as you all may know, about my favorite combination. RP1, Kerosene, Methane... these are ideal fuels for so many reasons. Our use of Liquid hydrogen can, in many ways, hold our rockets back. However as I think about fuels more, I am forced to remember how the cost of organic fuels has gone up a ton recently. Perhaps hydrogen will be more important in the near future as the cost of kerosene will go up even more.

It is sad that the N1 never flew to orbit (or even space?) and that the remaining parts were just tossed around parks. One fuel tank became the roof of a gazebo.

Monday, August 11, 2008


"Skylab was launched 14 May 1973 by a Saturn INT-21 (a two-stage version of the Saturn V launch vehicle) into a 235 nautical mile (435 km) orbit. The launch is sometimes referred to as Skylab 1, or SL-1. Severe damage was sustained during launch, including the loss of the station's micrometeoroid shield/sun shade and one of its main solar panels. Debris from the lost micrometeoroid shield further complicated matters by pinning the remaining solar panel to the side of the station, preventing its deployment and thus leaving the station with a huge power deficit. The station underwent extensive repair during a spacewalk by the first crew, which launched on 25 May 1973 (the SL-2 mission) atop a Saturn IB. If the crew had failed to repair Skylab in time, the plastic insulation inside the station would have melted, releasing poisonous gas and making Skylab completely uninhabitable. They stayed in orbit with Skylab for 28 days. Two additional missions followed on 28 July 1973 (SL-3) and 16 November 1973 (SL-4) with stay times of 59 and 84 days, respectively. The last Skylab crew returned to Earth on 8 February 1974."

This was the early history... The rest is a bit more depressing (to be fair the whole project had problems.) You see Skylab needed to be boosted from time to time to maintain orbit. There were several plans to do this, but none came about. Towards the end, it was planned that space shuttle visits would repair and boost the station from time to time. But the shuttle came online later than expected, and solar activity increased.

"Increased solar activity, heating the outer layers of the Earth's atmosphere and thereby increasing drag on Skylab, led to an early reentry at approximately 16:37 UTC 11 July 1979. In the weeks leading up to the reentry, ground controllers had re-established contact with the six year old vehicle, and were able to adjust its attitude for optimal reentry dynamics. Earth reentry footprint was a narrow band (approx. 4° wide) beginning at about [show location on an interactive map] 48° S 87° E and ending at about [show location on an interactive map] 12° S 144° E, an area covering portions of the Indian Ocean and Western Australia. Debris was found between Esperance and Rawlinna, 31–34°S, 122–126°E. The Shire of Esperance fined the United States $400 for littering, a fine which, to this day, remains unpaid."