Accidents in Space
“Some say risk nothing, try only for the sure thing,
Others say nothing gambled nothing gained,
Go all out for your dream.
Life can be lived either way, but for me,
I’d rather try and fail, than never try at all, you see.”
-William F O’Brien.
Accidents in space add an extra layer of threat to them because mitigating risk and finding resources can be very difficult. In this blog, I have summarized my top 3 aerospace accident details.
Top 3 human spaceflight missions till date according to me are:
1) Luca Parmitano’s EVA
Launch vehicle: Soyuz TMA-09M
Crew: Fyodor Yurchikhin of Roskosmos, Karen Nyberg of NASA and Lucs Parmitano of the European Space Agency.
Mission summary: Expedition 36/37: to install power-cables, retrieve material research samples (MISSE - 8) and accomplish a number of maintenance tasks, installation of a couple of radiator grapple bars previously flown up on SpaceX’ CRS-2 mission. The EVA was part of preparations for the new Russian multipurpose module planned to replace the Pirs docking compartment by the end of 2013.
Launch date: 28 May 2013.
Return Date: 11 November 2013
A completely unexpected and potentially deadly water leak in the spacesuit’s helmet nearly drowned Italian astronaut Luca Parmitano, forcing NASA to abort the spacewalk to get him to safety. One notable learning outcome of this incident was that its severity was heavily undermined. The major significance of this incident, according to me, was the identification of modifications to the EVA hardware and enable various means of achieving a greater degree of confidence in it by investigation. A number of root causes leading to the mishap were identified and a list of recommendations to mitigate these risks was proposed. Some important root causes were: inorganic materials blocking the EMU water separator drum holes, EVA 23 was conducted without recognizing the EMU failure that occurred in EMU 22, the EVA was not terminated as soon as water was reported in the helmet, the water in the helmet was incorrectly attributed to that from the drinking bag, EMU hazard report did not identify the hazard, Luca was unable to communicate the severity of his condition after the terminate call and no one applied knowledge of the physics of water behavior in zero-g. Yet, based on what they knew at the time, the ground control team performed admirably. Some of the key problems with the EMU were thrown in the spotlight after the investigation of this incident such as the helmet antifog material was problematic and the CO2 sensor has a history of failing during EVA due to excess moisture. The efficacy of some hardware systems was questioned such as reliability of the Helmet Purge Valve, weaknesses in the 6 year in-orbit certification of the EMU that could lead to premature failures, constantly changing water quality and chemistry in multiple onboard ISS systems and the sensitivity of the ISS Systems to these changes, general inability to access flight hardware to perform training of personnel, validating procedures or performing tests for the flight control and engineering teams and no backup EVA capability if the need for a contingency EVA arises. In order to avoid such incidents in future, a number of recommendations were relayed across the departments, such as, instructors should ensure that training includes use of failure scenarios for integrated and stand-alone simulations, all instances of free water and contamination in the EMU are documented and investigated with corrective action taken, investigate alternate materials that effectively perform the helmet anti-fogging function without the risk of eye irritation and alternate CO2 sensor designs that eliminate the sensitivity to moisture.
2) Apollo 10: Snoopy moon mission
Launch vehicle: Saturn-V AS-505
Crew: Thomas P. Stafford, John W. Young, Eugene A. Cernan.
Mission summary: Dress rehearsal for a Moon landing brought the Apollo Lunar Module 15.6 km from the lunar surface, at the point where powered descent would begin on the actual landing. Practicing this approach orbit would refine knowledge of the lunar gravitational field needed to calibrate the powered descent guidance system to within 1.9 km needed for a landing.
Launch date: 18 May 1969.
Return date: 26 May 1969.
It was the first flight of a complete, crewed Apollo spacecraft to operate around the Moon. Objectives included a scheduled eight-hour lunar orbit of the separated lunar module, or LM, and descent to about nine miles off the moon's surface before ascending for rendezvous and docking with the command and service module, or CSM, in about a 70-mile circular lunar orbit. Pertinent data to be gathered in this landing rehearsal dealt with the lunar potential, or gravitational effect, to refine the Earth-based crewed spaceflight network tracking techniques, and to check out LM programmed trajectories and radar, and lunar flight control systems. One of the most notable features of this mission was how human error in handling the systems onboard the spacecraft would cause trouble towards the completion of the mission and put human lives in danger. While carrying out the LM separation procedure, the vehicle started an unexpected and un-commanded maneuver. Turned out, this was a test of the Apollo guidance system. The crew were to test the abort guidance system (AGS) instead of the primary navigation guidance system (PNGS) they were used to using. The AGS had 2 basic control modes, “attitude hold” and “automatic”. In automatic, the computer would take guidance and start looking for the command module, which was not in range and not what the crew wanted to do. In correcting for a minor altitude disturbance, the crew had cycled the AGS switch, but put it in wrong position (the automatic instead of attitude hold), resulting in frantic gyrations as it tried to find the command service module (CSM). Hence, we learn that all manually operated systems can be vulnerable to human errors and hence, should be designed as carefully as possible. Also, the crew should be well educated and trained to minimize the risk of these errors. Another noteworthy point was the reason why the mission designers didn’t fill enough fuel in the LM as that would tempt the humans onboard into carrying out an actual landing over the moon’s surface, whereas, if they knew they didn’t have enough fuel to take off from the moon’s surface incase they land, they would stick to the original mission objective, which was to descend only upto 15.6km above the lunar surface. This sheds light on how control over a mission can be established by taking the human behavioral tendencies into account.
3) STS-126 EVA: Astronaut lost tool-bag during spacewalk
Launch vehicle: Space Shuttle Endeavor.
Crew: Christopher Ferguson, Eric A. Boe, Donald Pettit, Stephen G. Bowen, Hiedemarie Stefanyshyn-Piper, Robert S. Kimbrough, Sandra H. Magnus, Gregory Chamitoff.
Mission summary: Deliver equipment and supplies to the station, to service the Solar Alpha Rotary Joints(SARJ), and repair the problem in the starboard SARJ.
Launch date: 15 November 2008.
Return date: 30 November 2008.
During the first EVA of STS-126, as Stefanyshyn-Piper was preparing to begin work on the SJRC, she noticed a significant amount of grease in her tool bag. Mission Control managers instructed her to clean up the grease using a dry wipe, and while she was doing the cleanup, she accidentally pushed aside the bag. The bag floated aft and starboard of the station, and did not pose a risk to the station or orbiter. The bag and its contents entered Low Earth Orbit as space debris, where it eventually burned-up as it entered the Earth's atmosphere west of Mexico on August 3, 2009.
After taking an inventory of the items inside the lost bag, managers on the ground determined that Bowen had all those items in his bag, and the two could share equipment. While it extended the EVA duration slightly, the major objectives were not changed. The estimated value of the equipment lost is US$100,000.
During the Mission Status Briefing, lead International Space Station Flight Director Ginger Kerrick said that there was no way to know what caused the bag to come loose. We don't know if perhaps the hook just came loose inside the bag," Kerrick said.
The point worth noting in this EVA is that it was not the only one which involved inadvertent releases of equipment. There have been atleast 40 such cases costing the government millions of dollars. We can note the dire need of designers to come up with better ways to solve this particular problem.
References:
1) http://www.nasa.gov/sites/default/files/files/Suit_Water_Intrusion_Mishap_Investigation_Report.pdf
2) https://www.nasa.gov › mission_pages › apollo › missions › apollo10
3) https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=29&ved=2ahUKEwjerM-70sXkAhVumK0KHeqJC60QFjAcegQIABAB&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHeidemarie_Stefanyshyn-Piper&usg=AOvVaw0DtCMYvPYF-BLPCYwM1NPY