Genesis Suffers A Crash Landing
|Helicopter watches over Utah desert crash site. The science canister from the Genesis mission was moved into the cleanroom at the U.S. Army Dugway Proving Ground in Utah early Wednesday evening. First, a team of specialists plucked pieces of dirt and mud that had lodged in the canister after the mission’s sample return capsule landed at high speed in the Utah desert. The Genesis team will begin examining the contents of the canister on Thursday morning. |
The Genesis sample capsule crash-landed today, after its parachutes failed to deploy. The plan was to have the capsule float down on two separate parachutes, and then, before it hit the ground, it was to be scooped up by helicopters hovering nearby. Instead, the capsule plunged to the ground like a stone.
"As we exceeded our expected timeline for the drogue shoot to deploy, our hearts started to race a little faster, and before we knew it, it was on the ground," says Don Sweetnam, Genesis project manager.
The capsule entered the atmosphere at 25,000 miles per hour, creating a fireball in the skies over Oregon. Air friction was the only thing that slowed the capsule down, and by the time it hit the ground at the U.S. Air Force’s Utah Test and Training Range it was traveling 193 miles per hour.
The force of the impact partially buried the capsule, so the recovery team will need to dig it out of the ground. Upon first inspection, the capsule appeared to have cracked open, and the sample canister inside the capsule also may have been breached. The state of the collector materials is unknown at this time.
"If we don’t have anything that keeps us from bringing shovels out and start digging – for instance, needing protective gear for the people out there – we’re talking a couple of hours [to decide] whether we’re taking it out whole or taking out the science canister piecemeal," says Don Sevilla, Genesis payload team leader. He estimates that the capsule will be brought to the temporary clean room set up at Michael Army Air Field sometime today.
The drogue shoot was supposed to deploy when the capsule was at an altitude of 108,000 feet. This would have slowed the capsule down to subsonic velocities. The main parachute, a parafoil, was supposed to deploy six minutes later, at an altitude of 20,000 feet.
But the pyros that were designed to release the parachutes did not fire. These unfired pyros are now a hazard for the recovery team as they try to dig the capsule out of the ground. The recovery team also must be wary of sulfur dioxide that could escape from the onboard battery, so they are wearing breathing apparatus while they air out the capsule.
Although, "airing out the capsule doesn’t appear to be too much of a problem now," comments Sevilla.
The battery may be the reason for the parachute failure. Scientists had reported earlier in the mission that the battery on the capsule seemed to be overheating. Bob Corwin, Genesis recovery team chief, says the battery was within five degrees of overheating during atmosphere entry.
"If you had completely no battery, once you don’t fire the first pyros, it doesn’t matter, you don’t fire the rest of them," says Corwin.
Other possible problems include the capsule not sensing the G-load that would have triggered the pyros, or a problem in the electronics that fire the pyros.
The helicopter rescue mission was dependent on the parachutes working properly. The helicopters were equipped with long rescue lines fitted with a hook at the end. The hook was going to grab onto the parafoil, allowing the helicopter pilots to set the attached capsule gently down to Earth. But without the parachute, the helicopters had nothing to grab on to.
|Parachute and parafoil failures led to desert impact on Sept. 8.|
At previous press conferences, the mission scientists only had discussed what could happen if the helicopters failed to grab the parachute. The damage was expected to be extensive if the capsule parachuted to the ground. The parachutes would have slowed the capsule down to about 20 miles per hour, but that still would have been enough force to shatter the collector panels inside the capsule.
Since the capsule zoomed to the ground at 193 miles per hour, the damage is likely far worse than then the helicopter-miss scenario. Sevilla says if the capsule doesn’t have too much structural failure, and if it is not embedded too far into the ground, they should be able to manhandle it into a cargo net that could then be flown to the clean room nearby.
"I venture to state that because the canister has been breached, there’s some issue with that," says Sevilla.
"We want to maintain our precious cargo. The collectors have been returned to Earth, and we don’t want them to spill out."
The Genesis spacecraft gathered billions of atoms that streamed off the sun’s corona over the past two years. These solar wind samples are contained in thin collector wafers made of gold, sapphire, silicon and diamond. The atom samples are not deeply embedded in the collectors, but reside in a shallow surface area. Scientists will have a delicate task ahead of them as they try to put the pieces back together without affecting the samples.
|Genesis re-entry with solar wind in tow.|
Because the collectors are made of different materials, this should help the scientists puzzle out which piece fit together. In addition, the five individual arrays each are a different thickness.
Sweetnam says that before the capsule entered the atmosphere, everything looked great.
"I have run through in my head the mental scenario of every step of the way, and boy, it clicked off perfectly today. But there’re a lot of things that have to happen in series. We just didn’t get the last two or three of them done," says Sweetnam.
NASA Headquarters will appoint a mishap review board within 72 hours. The board will look at all the data, such as film of the spacecraft coming in and the telemetry leading up to entry, and then decide what to do next.
The Stardust mission is scheduled to bring its cometary samples back to Earth in January 2006, and the entry design for Stardust is similar to the Genesis design. In a way, Stardust’s fate is sealed, because there’s no way for mission scientists to make changes to it as it travels back to Earth. But by determining which component failed on Genesis, scientists might be able to adjust Stardust’s entry for a safer landing.