# Can Curiosity pay InSight a visit?

InSight landed “just” 600 kilometers from Curiosity’s landing site. Can Curiosity make its way there for a rendezvous? Are there any plans for this?

• – Mark Nov 28 '18 at 4:51
• I once had the same thought too, it's really fascinating, though. However, this action is not beneficial by any means; neither to Curiosity nor InSight. Plus some other reasons (e.g. the travel speed of Curiosity rover and their expected lifetime stated by @Hobbes below), probably InSight would've already shutdown long ago before the rover could even finishes 1/10 of the total distance to reach InSight. Clearly to see the visit is explicitly impossible and that's why it was never planned. – Boosted Nub Nov 28 '18 at 6:23
• There is no reason for them to visit, that data costs a lot of money, why take duplicate data by putting them in the same location? – DonQuiKong Nov 28 '18 at 8:14
• @DonQuiKong "duplicate" wouldn't be a appropriate adjective over here. Cusiosity and InSight do not share the similar mission on Mars. Curiosity rover aims to explore and investigate the Martian climate and geology while the other side; InSight lander is designed as a stationary machine that studies interior core of Mars. – Boosted Nub Nov 28 '18 at 8:30
• @si_the_nibba but they share (aka both have it) at least some sensors, right? – DonQuiKong Nov 28 '18 at 8:49

## 3 Answers

No.

Curiosity took 3 years to travel 10 km. There are no plans to visit InSight, Curiosity's mission is to survey Gale Crater and climb Mount Sharp.

Curiosity can travel on the order of 100 m/day. At that rate it would take 20 years to get to InSight. The RTG can provide enough power for about 14 years. The wheels are rated for ~40 km depending on the terrain.

Curiosity can only drive for a few hours per day: driving takes 500 W and the RTG only produces 100W, so it has to stop regularly to recharge its batteries.

• Additionally, curiosity driving around inSight would be picked up by the seismograph and create bad data. – Dragongeek Nov 27 '18 at 14:44
• @Hobbes Identify? Yes. Filter out? Not necessarily. Can you say for sure whether that particular wobble on the graph is from Curiosity's wheels slipping in the dust, or some interesting geological phenomenon that just happened to be at the same time? At the very least it'd black out InSight for however long Curiosity is driving near it. – Nic Hartley Nov 27 '18 at 18:22
• Sadly the Mars Probe edition of BattleBots isn't coming around anytime soon... – TemporalWolf Nov 27 '18 at 20:01
• I think the question deserves a better answer than a two sentence shut-down. Is 100m/day really close to some limit of the rover itself, or a function of super-cautious route planning and obstacle avoidance? Also considering Spirit and Opportunity's ten year runs, what does "design lifetime" really mean here? Wouldn't decay of the RTG over time be more of an absolute limiting factor. – uhoh Nov 28 '18 at 1:10
• Made a 2-paragraph shutdown instead. – Hobbes Nov 28 '18 at 8:24

tl;dr: I think it is possible, if Matt Damon's life depended on it.

@Hobbes's answer is certainly the most reasonable view and likely to be true. But let's look at this from the standpoint of absolute limits.

## Speed

this answer says in part:

Curiosity... has a rated travel speed of 200 meters per day, but this is mainly due to navigation restrictions rather than power limitations. Improved techniques might be able to get it up to its rated driving speed of 90 meters per hour, and since the rover's RTG operates just fine at night (unlike Opportunity's solar panels), continuous driving might be possible. In this case, it would take about 1200 days for Curiosity to reach Spirit, assuming it didn't need to detour around any major obstacles. This is, of course, assuming that the wheels don't wear out.

This Quora answer says:

The rover has a top speed on flat hard ground of 5 centimeters (2 inches) per second. However, in order to ensure a safe drive, the rover is equipped with hazard avoidance software that causes the rover to stop and reassess its location every few seconds. So, over time, the vehicle achieves an average speed of 1 centimeter per second. The rover is programmed to drive for roughly 10 seconds, then stop to observe and understand the terrain it has driven into for 20 seconds, before moving safely onward for another 10 seconds.

Wikipedia's Curiosity_(rover) Specifications says:

Based on variables including power levels, terrain difficulty, slippage and visibility, the maximum terrain-traverse speed is estimated to be 200 m (660 ft) per day by automatic navigation. The rover landed about 10 km (6.2 mi) from the base of Mount Sharp,(officially named Aeolis Mons) and it is expected to traverse a minimum of 19 km (12 mi) during its primary two-year mission. It can travel up to 90 m (300 ft) per hour but average speed is about 30 m (98 ft) per hour.

I'll look at these two values to try to bracket the optimistic range, ignoring the reality that terrain avoidance and navigation issues would require a path much longer and slower.

@Hobbes has just reminded me that the RTG's power output is much lower than needed for driving, so just like our friend Matt Damon, it's necessary to charge a lot and drive a bit and charge a lot more. I'll ballpark it at 2 hours of driving per day.

   m/h           km/day       days/600 km   years/600 km (at 2 hour/day)
(100)            0.2            3000            8.2
90            (0.18)           3300            9.1

36 to 180    (0.07 to 0.36)   (8300 to 1700)  (23 to 4.6)   Quora answer


There is in deed plenty of life in the RTG, and if Matt Damon's life depended on it, it is certainly conceivable that they'd try for it in the movies.

@Hobbes' other answer at least has faith in curiosity's grade-climbing capabilities.

## Wheels

But in the movies, curiosity's wheels would hold out. And that may not be the case in reality.

The question Curiosity wheel damage and its several answers point out that the wear rate of Curiosity's wheels is an issue partly because they are made from thin titanium aluminum and rocks are sharp. A 600 km (minimum, it would likely be longer in total) drive would probably tax these wheels beyond their maximum. Between the wheels and all of the other systems, the chance for mechanical failure is great.

## Thermoelectric power

Pu238 has a half-life of about 88 years; even in 10 years that only represents a loss of 8% in thermal power. However, thermoelectric power may suffer worse, the solid state devices may degrade over time.

## Power of positive thinking

On the flip side though, Spirit an Opportunity put on quite a durability show, lasting of the order of a decade and going tens of kilometers. Considering that Curiosity's engineering builds on that experience, it's impossible to say that this trip is impossible.

## 0.75 mm titanium aluminum is susceptible to damage by some of Mars' more pointy rocks.

From Space.com's Wheel Worries: Mars Rover Curiosity Dealing With Damage Click for full size.

• Curiosity's daily range is limited by available power (see the last section of my answer) – Hobbes Nov 28 '18 at 14:43
• @Hobbes I had a hunch I could coax you to one more ̶s̶e̶n̶t̶e̶n̶c̶e̶ paragraph ;-) I'll go back and re-do everything now, thanks! – uhoh Nov 28 '18 at 14:45
• The linked article seems to indicate the wheels are made of aluminum and not titanium. Dicussed here: space.stackexchange.com/questions/3597/… – Darren Nov 28 '18 at 17:17
• @Darren thanks for that, I've fixed that and included your link. – uhoh Nov 28 '18 at 23:05
• Same thought went into my mind that Matt Damon's movie The Martian would be a great reference (my favourite movie as well). But it was too difficult for me to convert everything into a good, appropriate & relevant answer. – Boosted Nub Nov 29 '18 at 2:53

It is possible, as uhoh demonstrated, to go the distance between the two, although it would take a long time. But the terrain makes that somewhat unlikely. I've pulled the elevation map, the yellow marker is where Curiosity is, the red circle is roughly where InSight is (I couldn't get a better location, unfortunately)

The first obstacle that Curiosity would have to tackle is getting out of Gale Crater. It is close to one of the flatter exit ramps, but still, it wouldn't be easy.

Once it leaves Gale Crater it is in a reasonable flat area, and could probably safely make most of the trip. The danger, however, is the area where InSight is itself. The area was deliberately chosen to be dusty, to make putting the drill in to the surface of Mars easier then hard rock. That is poor conditions for driving, and could result in it getting stuck.

The biggest reason, however, is that there just isn't a good reason for Curiosity to visit InSight. Gale Crater is a fantastic area to explore, and InSight will already have its site explored quite carefully by that time, no reason to waste a billion dollar rover to study an area that is already studied.

• The supporting sources used in @Hobbes' other answer seem more optimistic about Curiosity's climbing abilities. What is is specifically about the terrain that makes you feel it is unlikely? – uhoh Nov 28 '18 at 16:15
• The sandy nature of the landing spot of InSight, but I mentioned that it should be able to climb out of the crater without issue. – PearsonArtPhoto Nov 28 '18 at 16:22
• I see. 2nd sentence "But the terrain makes that somewhat unlikely." I think "terrain" refers to the topology, not the nature of the regolith. Maybe instead of "terrain" it's better to just say the large expanse of sandy soil"? – uhoh Nov 28 '18 at 16:25