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To save money, U.S. astronauts in space, grabbing a 4-ton satellite with their bare hands for repairs

Grabbing a 4-ton satellite for repair

By ApostolakisPublished 2 years ago 9 min read
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Satellite

In one of the most thrilling emergency repair missions in the history of space flight, three astronauts left the cabin and decided to give it a try by grabbing the 4-ton satellite, which was moving and spinning at high speed, with their bare hands. If there is a slight failure in this process, leaving the astronauts only a short 20 seconds to save themselves. It can be said that life is at stake, life, and death only in a moment.

Failure of the launch mission.

In the late 1980s, with the booming development of electronic products such as cell phones, people are more closely connected.

Behind this, satellites in space were instrumental. As the demand for communication increased, the number of satellites increased accordingly. However, the design of the previous Communication Satellite 5 could no longer keep up with the soaring demand for communication.

For this reason, IOSAT decided to develop a new generation of communication satellites, Intelsat 6, to replace the outdated satellite 5. 6 was the first satellite to be developed, for $300 million that year. It is a spin-stabilized satellite, designed for a service life of 13 years, with a diameter of 3.6 meters, an altitude of 11.7 meters, and a weight of 4 tons.

Each satellite can turn 120,000 call lines at the same time, and also 3 TV channels. Now the cell phone age some not enough to see. But in the late 1980s, such a satellite can meet the needs of several countries.

On October 27, 1986, everything was ready for the launch of Intelsat 6, and the first satellite successfully reached its intended orbit. On March 14 of the following year, the second satellite was also launched, but when the satellite went to space, the command center monitoring data showed anomalies.

Because the rocket did not reach the intended orbit, the satellite was "unloaded" midway. At this time, the satellite orbit was elliptical, with an apogee of 349 kilometers and a perigee of only 169 kilometers. At this orbital altitude, the satellite will face the risk of crashing into the atmosphere.

Fortunately, although the satellite failed to launch, the performance was not affected. Under the control of the ground command center, the satellite activated its tail thrusters and lifted its orbit to an apogee of 407 km and a perigee of 259 km.

At this position, there is no risk of satellite crash for the time being, but the lifetime of the satellite will be greatly reduced. At the high speed of the satellite, the reactive oxygen atoms in the near-Earth orbit will corrode the welded interface of the solar panels, and its service life will be one-tenth of its design life, i.e., more than one year.

At this point, we are faced with a choice between re-launching a new satellite or salvaging the failed satellite.

Space shuttle chases satellite

If it were now, the satellite would undoubtedly be scrapped and a new one re-launched. But in those days, there was another option, which was maintenance.

This happened because the shuttle had not been retired at that time, and the mechanical arm on the shuttle could grab the satellite and install a new launcher for it, which is not possible for the shuttle nowadays.

If a satellite was only worth tens of millions, it would undoubtedly be re-launched because it cost much more than that to send the shuttle, but a satellite is worth 300 million, which was more than 300 million more than 30 years ago.

So there were two dimensions to consider at the time: time and cost.

If the cost is the same, which time is faster, and which option will be chosen? At the same time and cost, the cost is lower which option will be chosen.

After the final calculation, it takes more than two years to repair or re-launch a new satellite, but the satellite repair cost is just over $100 million, only one-third of the cost of launching a new satellite.

Then the final bill is finalized, the satellite is captured, and a new launcher filled with fuel is installed in the shuttle's cargo bay and re-layered with solar panels. The satellite is then released. After the shuttle leaves the satellite, the ground command center will activate the launcher and push the satellite into its intended orbit.

Space Shuttle Endeavour carried seven astronauts into space on May 7, 1992.

This was the first mission of the Space Shuttle Endeavour. After entering space, the shuttle chased the satellite. The satellite was traveling at 28,000 kilometers per hour, and the shuttle spent three days looking for it.

Finally, it caught up with the satellite in a 360 km orbit, only 15 meters away from it.

The first satellite capture failed.

Because it is a spin-stabilized satellite, it spins once per second. The first step for the shuttle to bring the satellite back to Earth is to stop the satellite from spinning, then catch it with a mechanical arm and fix it in the shuttle's cargo bay for maintenance.

Otherwise, in the face of the constantly rotating satellite, once the arm is close, it may be a lose-lose situation.

Therefore, the burden of stopping the satellite's rotation falls on the astronauts. After the satellite maintenance was determined, the astronauts have been undergoing two years of training in the water. The astronauts brought some mechanical devices with them to train how to make the simulated satellite stop spinning.

The first one out of the cabin was Pierre Soter. He stood on the platform at the top of the robot arm. As in the training, he is holding a 4.5-meter-long, 72-kg mechanical device. He tries to insert it into a structural ring in the satellite's tail to stop it from spinning, and then he uses the shuttle's robotic arm to capture the satellite.

After two years of training, it was very difficult to insert the mechanical device accurately into the bottom of the satellite in a weightless space environment, where both the shuttle and the satellite were flying at high speed and the satellite was still rotating.

To prevent the satellite from being damaged, we had to be careful. With every little distance, it was just impossible to insert the structural ring of the satellite accurately. After several hours of trying, not only did it fail, but the satellite was shaken. Finally, the captain ordered the exhausted Soter back to the cabin to rest.

After a day of rest, Soter went out of the cabin again the next day. And the first day, as in the exchange with his companions, he said reluctantly: the satellite turned too fast, whenever he tried to catch it, he ran away again.

This time, Soter went back to the cabin, to sum up, his experience. He concluded that it was impossible to catch the satellite with a mechanical device without destroying it. The main reason was that the space environment was very different from the simulated training in the water.

In the space environment, the spacesuit will become much stiffer, which will not only cause mobility problems but also make the palm feel worse. And with a satellite weight of 4 tons, it is easy to get rid of the mechanics even if they are close to the proper position. It would be difficult for one person to stop it.

Grabbing the satellite with bare hands

Was this mission just a failure?

Don't! The good show is yet to come.

NASA experts and Endeavour astronauts discussed the situation on the spot and finally came up with an amazing plan to catch it with their bare hands since the mechanical device was not good enough. Since a person's strength is not enough, it will be three people together.

This program is very risky behavior. If the astronauts want to grab a 4-ton satellite with their bare hands, they will face two kinds of risks.

1. The risk faced by the astronauts

The shape of a satellite flying in space is not a smooth, spherical object. Satellites have a sharp edge. When astronauts grab it with their bare hands, the spinning satellite is likely to cut through the spacesuit.

Because the interior of the suit is under pressure, once its rupture reaches 0.6 cm, the suit will release pressure. Scientists speculate that after the loss of pressure inside the suit, astronauts have only 20 seconds to save themselves in space. This time is far from enough for spacewalking astronauts, so the astronauts' lives are at stake.

2. The risk of space shuttle and satellite

The movements of the three astronauts must be consistent and the strength must be controlled. Moreover, they can't fire at the same point at the same time. They must control the satellite at an angle of 120 degrees.

Because the satellite rotates faster, if the force is not consistent, the attitude of the satellite will change. If the satellite rotates at 28,000 kilometers per hour, the change in its attitude will have very serious consequences.

The consequences are very mild, and the satellite will crash into the atmosphere, causing the entire mission to fail.

If the consequences are serious, the space shuttle and satellite, two high-speed objects in such proximity collide, then let's not talk about the mission, and the seven astronauts will never return to Earth.

After several days of space flight, the shuttle's fuel could no longer support them to stay in space. After a short break and discussion, the plan to catch the satellite with bare hands had just begun on May 13.

At 5:12, Souter stepped out of the shuttle for the third time, followed by astronauts Richard Schieb and Thomas Akers. After the three astronauts reached their designated positions and secured them, the remaining astronauts flew the shuttle slowly closer to the satellite until the three astronauts could reach out and touch the satellite at arm's length.

After all the preparations, at 7:59 pm that day, with a command, three astronauts from different directions at the same time to reach out to the satellite. The satellite wobbled a bit after it was suddenly subjected to an external force. Finally, Heeb seized the opportunity to tame the 4-ton behemoth by grabbing the satellite with one hand and quickly attaching the mechanism to the structural ring at the bottom of the satellite with the other.

A robotic arm on the shuttle then delivered the satellite to the cargo bay, where other astronauts then spent the day repairing the satellite, replacing the engines and the interfaces corroded by oxygen atoms, leaving the entire satellite with a new look.

After two years of ups and downs, the satellite was finally returned to orbit.

Conclusion:

Art comes from life. When watching a science fiction movie, a small spaceship catches up with the mother ship which is connected by high-speed rotation. With the rousing music added, it makes people feel thrilled.

But in reality, there is such a group of space explorers, without the passionate music to add, but facing the same dangerous situation, controlling a 4-ton rotating satellite with their bare hands. In the process, if something goes wrong, they will never be able to return to Earth.

Science
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About the Creator

Apostolakis

To make scientific, diligence is the mother of success

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