NASA makes flying to Mars look easy, but cross your fingers for InSight anyway

Weather permitting, NASA will send its first spacecraft to Mars since 2013 early on Saturday morning. The InSight mission, designed to study the interior of the Red Planet, is the agency’s first Martian lander—a stationary vehicle as opposed to a rover—since the Phoenix spacecraft touched down on Mars in 2008.

We kind of take it for granted that everything on a mission like this will work. NASA really makes it look easy—the last eight rovers, landers, and orbiters it has sent to Mars have all pretty much met or exceeded expectations. But the road to Mars is littered with dozens of failures.

In fact, no other country has ever landed anything on the surface of Mars that survived for more than a few seconds. So with the world’s mixed record of success, here’s a look at a few potential pitfalls that InSight must avoid before it can burrow 5 meters into Mars and study the interior of the planet in-depth for the first time.

Launch

For many missions, the rocket launch is the most dangerous part of the whole enterprise, as rockets sometimes go all explode-y. For InSight this may be less of a concern because the spacecraft will launch on arguably the most reliable rocket in the world, the Atlas V booster. A two-hour launch window opens at 4:05am PT on Saturday (11:05am UTC). Dense fog is a weather concern, but officials have indicated that the Atlas V can probably launch anyway.

The novelty with Saturday’s launch is that it will occur from Vandenberg Air Force Base on the West Coast, north of Los Angeles. No interplanetary mission has ever launched from the West Coast of the United States, as it is more beneficial from an orbital mechanics point of view to launch due east, from Florida, with the Earth’s rotation.

However, InSight is a smaller spacecraft, with a launch mass of 721kg. The Atlas V rocket, manufactured by United Launch Alliance, has more than enough oomph to get the spacecraft into a proper Mars trajectory by launching south from Vandenberg, over the Pacific Ocean. It doesn’t even need any of the solid rocket boosters that can be attached to the rocket for an additional kick off the launch pad.

So why isn’t InSight simply launching from Florida? The reason is that the “range” on the East Coast is more congested with upcoming launches this month, including two by SpaceX. InSight has a daily launch window until June 8, 2018 to get off the ground.

Arrival and landing

After a six-month cruise to Mars, InSight should arrive at the Red Planet in November. Presently, NASA plans to attempt to land InSight on Mars on November 26, or the “Black Monday” following Thanksgiving. One scientist joked Thursday during a set of briefings that the public can watch the landing while doing their online shopping.

The last time NASA attempted to land a spacecraft on Mars came in 2011 with the Curiosity rover. For that understandably hyped landing, NASA used a never-tried-before skycrane system because Curiosity had a landing mass of about 1 ton. InSight is a significantly smaller vehicle with a landing mass only a little more than one-third that of Curiosity, so theoretically, it should be easier to get down to the surface.

It also has a pedigree. The InSight lander builds on the design of NASA’s Mars Phoenix lander, which touched down in 2008. It will use a combination of parachutes and then 12 descent engines to slow from an atmospheric entry velocity of 6.3km/second. Even so, given that Mars is littered with failed landers, we’ll be giving thanks a few days later than normal this year (hopefully).

Spacecraft

Finally, the spacecraft has to work once it reaches the ground. After landing, InSight will spend about two months slowly deploying and testing its 2.4-meter robotic arm and scientific instruments. It will then begin its science activities. The heat probe is scheduled to deploy and begin burrowing into the Martian soil about 17 weeks after landing. The prime mission is scheduled to last about two years.

It is by no means a certainty that InSight will, in fact, work, as it is bringing some entirely new technologies to the surface of another world. NASA had originally intended to launch the spacecraft two years ago, before engineers discovered problems with the spacecraft’s seismometer system.

The seismometer itself worked fine, but several times during 2015, engineers found a leak in the 22cm sphere that creates a vacuum so that the instrument can function on the harsh surface of Mars. Their temporary fixes didn’t address the problem. NASA now says the problem has been fixed.

In any case, there will be no ability to fix a significant problem with the seismometer—or the burrowing probe, for that matter—once InSight is on Mars. So if everything works with the launch, landing, and science operations, don’t think it was because it was easy. Millions of hours of work went into ensuring success, for which we should salute NASA, the spacecraft’s contractor Lockheed Martin, United Launch Alliance, and the dozens of other major contributors. (Because if something goes wrong, they will surely get the blame).

https://arstechnica.com/?p=1303149