NASA Prepares for Space Rescues

wallstreetprodigy23 copies and pastes "Space shuttle commander Steve Lindsey is preparing for a mission he hopes will never launch: the rescue of other astronauts in orbit. If a crisis arises during shuttle Discovery's planned return to flight in May, Lindsey and a crew of three could be called upon to lift off aboard sister ship Atlantis on an emergency mission that would be the first in the history of human space exploration. Rescue flights were hotly debated at NASA after shuttle Columbia broke up in the skies above Texas two years ago this Tuesday. Questions arose about whether Columbia's seven astronauts could have been saved. Because of the accident, NASA will have a backup shuttle and rescue crew ready for at least the next two flights in case another ship suffers damage similar to what brought down Columbia."

Comments

Re:Spot the problem first

[FrYGuY101]

People at NASA were aware that the foam hit the shuttle wing though, and simply dismissed it.

You can bet your ass if something similar happens on the next few flights, they're going to inspect the damage, rather than ignore it.

CAIB Recommendations

[SlashCrunchPop]

The Columbia Accident Investigation Board Recommendations say nothing about a rescue plan:

Recommendation One:

Prior to return to flight, NASA should develop and implement a comprehensive inspection plan to determine the structural integrity of all Reinforce Carbon-Carbon (RCC) system components. This inspection plan should take advantage of advanced non-destructive inspection technology.

This recommendation was issued because of the board's finding that current inspection techniques are not adequate to assess structural integrity of RCC, supporting structure, and attaching hardware.

Recommendation Two:

Prior to return to flight, NASA should modify its Memorandum of Agreement with National Imagery and Mapping Agency (NIMA) to make on-orbit imaging for each Shuttle flight a standard requirement.

This recommendation was issued because of the board's finding that the full capabilities of the United States Government to image the Shuttle on orbit were not utilized.

Recommendation Three:

Before return to flight, for missions to the International Space Station (ISS,) develop a practicable capability to inspect and effect emergency repairs to the widest possible range of damage to the Thermal Protection System (TPS,) including both tile and Reinforced Carbon Carbon (RCC,) taking advantage of the additional capabilities available while in proximity to and docked at the ISS.

Before return to flight, for non-station missions, develop a comprehensive autonomous (independent of station) inspection and repair capability to cover the widest practicable range of damage scenarios.

An on-orbit TPS inspection should be accomplished early on all missions, using appropriate assets and capabilities.

The ultimate objective should be a fully autonomous capability for all missions, to address the possibility that an ISS mission does not achieve the necessary orbit, fails to dock successfully, or suffers damage during or after undocking.

Recommendation Four:

Upgrade the imaging system to be capable of providing a minimum of three useful views of the Space Shuttle from liftoff to at least Solid Rocket Booster separation, along any expected ascent azimuth. The readiness of these assets should be included in the Launch Commit Criteria for future launches.

Consideration should be given to using mobile assets (ships or aircraft) to provide additional views of the vehicle during ascent.

If they implement everything as recommended there is no need for a rescue plan and I doubt such a plan would actually work, it seems more like a publicity stunt to reassure the masses.

Rescue of Columbia's crew as discussed by CAIB

[willith]

The Columbia Accident Investigation Report listed one permutation of a rescue mission that could have been launched to save Columbia, if anyone had realized the true severity of the damage to her wing. According to the report, a second shuttle (I believe it was Endeavour, but it's been a while since I read the report) could have been rolled out and launched in a matter of days, skipping the normal three-month pre-launch safety checklist.

The second shuttle could have rendezvoused with Columbia and brought to station-keeping directly below her, such that the two shuttles' cargo bays were facing each other (Columbia would have been orbiting upside-down and backward relative to the ground, as is standard). Columbia's crew could then have transferred to the rescue shuttle via tether.

All of this could have been done inside the week-long window before Columbia's consumables were exhausted; after the rescue, Columbia would have been de-orbited into the ocean.

One of the things that will be mandatory on all remaining shuttle launches will be for all shuttles to be able to rendezvous and dock with the ISS, in the event something like this happens again. This was not an option for Columbia, for a couple of reasons--she was unable to boost to the ISS's altitude, and she lacked the correct docking mechanism to couple with the ISS.

Re:Speed

[p3d0]

Why not just slow down a bit before entering the atmosphere?

Have you seen the rocket boosters they use to launch the shuttles? They'd need the same boosters to slow it down again. And then they'd need way, way bigger rockets just to lift those boosters into orbit in the first place. The total amount of fuel required is staggering.

Let me tell you the two most important things you need to know to get some idea of how staggeringly hard your proposal is to implement.

The first thing is the speeds involved. These guys are going 17,000 miles per hour. That's 7 times faster than a rifle bullet, and it weighs as much as 30 big SUVs. How do you propose to take this monster and make it "slow down a bit"? If they can't brake in the atmosphere, then need to use rocket power to slow back down to, say, 1,000 miles per hour (the speed of Earth's rotation at Florida plus a couple hundred mph) so they can land.

The second thing is even worse: the Tsiolkovsky rocket equation. It tells us how much propellant is needed to achieve a given speed change (impulse). This is not based on any particular rocket technology; it's a fundamental law derived directly from Newton's third law of motion (the equal-and-opposite-reaction one).

Tsiolkovsky's equation is calibrated to the exit velocity of the propellant. If you want your rocket's velocity to change by N times the propellant's exit velocity, its mass must reduce by a factor of e^N. In the case of the Shuttle going to orbit, N=2.7, and the "mass ratio" e^N=15.5, meaning that only about 1/15 of the vehicle makes it to orbit. The other 14/15 was rocket fuel.

If you want to deorbit the Shuttle using rockets, then you'll need to double your delta-V, because you must first go from zero to 17000, and then from 17000 back to zero. This gives N=2x2.7=5.4. However, this is too high, because you're not fighting air resistance and Earth's gravity when you're re-entering like you are when you're taking off. So let's be conservative and say it's only N=4.5. Then your mass ratio becomes 90, so the fuel tank needs to be 6.4 times larger than they already are! If you have seen the Shuttle's fuel tank, you know this is absurd.

The best thing about deorbiting in the presence of an atmosphere is that it costs no rocket fuel. However, it does have its dangers.