NASA revises Mars missions
Dec 10, 1999
NASA has lost contact with the $200 m Mars Polar lander and its two Deep Space microprobes. The three spacecraft were scheduled to land on the Martian surface on 3 December, but no contact has been established with the probes after they entered the Martian atmosphere. The failure of the missions, coming so close after the loss of the Mars Climate Orbiter earlier this year, has caused the agency to suspend and review all future missions to Mars.
NASA's Mission Control Center hoped that the Deep Space Two micoprobe had landed safely and gone into a 'sleep' safety mode. But all attempts to contact the probes have failed. During re-entry the spacecraft had to break communications with Earth, which means that no information about the probes' final moments exist. However, researchers at NASA suspect that a single event caused all three failures. The most probable explanation is that the protective covering of the spacecraft refused to eject before entering the Martian atmosphere, thereby preventing the microprobes from being launched. Another possibility is that all three craft could have been lost to the rocky Martian terrain.
The Mars Global Surveyor, which is in orbit around Mars, will now be repositioned over the Southern pole to look for the Mars Polar Lander descent parachute. "It is entirely possible that the Mars Polar Lander did a perfect descent, the parachutes came out, and the rockets fired, and we landed on a rock and tipped over," says Edward Weiler, head of NASA Space Science, "This entire failure could be due to fate."
Both NASA and the Jet Propulsion Laboratory(JPL) - which manages the Mars programme - are now investigating the failures. A number of programmatic and managerial problems are expected to be raised during their meetings. Earlier this year, for example, NASA discovered that a mix up between metric and imperial units led to the loss of the Mars Climate Orbiter mission. During a routine check on the Mars Polar Lander software NASA discovered some bugs which could also cause the craft's destruction.
The new setback calls into question NASA's policy of 'faster, better, cheaper' space missions as well as it's ambitious Mars programme. Two more spacecraft - Mars Surveyor 2001 orbiter and lander - are scheduled for the next launch window to Mars in 2001. Another lander with a small rover that would collect soil samples and fire them into orbit is planned for 2003, while a similar mission is planned for 2005. A French spacecraft is then meant to collect the samples and take them back to Earth by 2008.
All these missions will now be redesigned or rescheduled, for example, by making sure that engineers can receive information about the spacecraft as they enter the atmosphere. Significant changes in the management of future missions are also planned. "Clearly something is wrong, and we have to understand it," says Dan Goldin, NASA's director. "We're not going to just go rushing off and build a spacecraft just to meet an arbitrary  deadline."