Two miniature satellites no bigger than a shoebox are hurtling through deep space on a historic mission to Mars.

Key points

  • CubeSats are tiny satellites — a basic unit is a 10cm x 10cm box
  • No CubeSats have been into deep space until now
  • Two six-unit satellites called MarCO-A and MarCO-B are about to fly over Mars at the same time another spacecraft called the Mars InSight Lander touches down
The plan is to be in the right place, at the right time, to witness the landing of NASA's InSight spacecraft on the Red Planet on November 27, at about 7:00am AEDT.
At the same time Insight lands, the Mars Cube One (MarCO) satellites will pass 3,500 kilometres directly above and beam data back to Earth.
"The two spacecraft — MarCO-A and MarCO-B — will be performing a very tight choreographed dance with InSight," Brian Clement, who is working on NASA's MarCO project at the Jet Propulsion Laboratory, said.
Cruising at a speed of about 66,000km per hour the two satellites are currently just under 7 million km away from their destination.
But even before reaching Mars, the little satellites — nicknamed Eve and Wall-E — are punching above their weight.
This is the first time spacecraft this small, known as CubeSats, have travelled this far into space.
"We've travelled at this point almost 480 million km — that's a very long journey for a couple of CubeSats," Dr Clement said.

Challenges of deep space travel

Travelling over such long distances is very challenging.
"It requires having brand-new miniaturised technology and the ability to carefully manage the spacecraft," Dr Clement said.

Mars InSight mission

  • NASA's Mars InSight spacecraft will land on Mars on November 27
  • The mission is the first to study the interior of the Red Planet. It will have three experiments that measure the planet's temperature and seismic activity
  • As it lands on Mars, two miniature satellites will fly overhead and send data back to Earth
  • The InSight spacecraft is currently around 6.5 million kilometres away from Mars
  • The CubeSats are currently just under 7 million kilometres from Mars
  • The InSight mission, which is designed to go for two years, will be monitored by the Mars Reconnaissance Orbiter.
Packed into a 24cm x 36cm x 11cm box is a propulsion system, a navigation system, two cameras and a battery attached to two solar panels and a rectangle-shaped antenna known as a reflective array.
The mini-satellites were launched on May 5 on the same rocket as the InSight spacecraft, but since then all three spacecraft have been flying on their own trajectory towards Mars.
"We're navigating through deep space by ourselves, we're not attached to anything else," Dr Clement said.
"That requires the capability to have your own propulsion and your own navigation equipment, and you have to be very accurate in the navigation adjustments you make along the way."
It also requires the ability to withstand the harsh conditions of deep space.
As the little satellites venture further away from the sun, there is less solar power and heat.
"The spacecraft has to be able to make and store power in a pretty challenging environment," Dr Clement said.
"That power is being used to communicate, navigate, run all the systems on board, as well as keep the spacecraft at its operating temperature.
"We'll ultimately be at a distance where we'll have half the power we would have just from solar energy alone."

Hello Mars!

Wall-E got its first glimpse of the Red Planet last week in the first ever CubeSat happy snap of deep space.
As the spacecraft moves in towards Mars, the team will fine-tune the trajectories so the craft can rendezvous with InSight.
"As InSight comes in to land MarCO-A and MarCO-B will pass over the landing site in such a way that we maximise our ability to listen to InSight's radio signals," Dr Clement said.
While the InSight mission is largely being monitored by another spacecraft known as the Mars Reconnaissance Orbiter, the first signals from the landing will come from the CubeSats.
All going to plan, they will rotate so their antenna picks up signals from InSight and relays them directly to the Deep Space Network ground stations on Earth — at the speed of light.
"It takes eight minutes to send a command up, and the same to come back," Dr Clement said.
"The landing will almost be done by the time that MarCO send the data back."
After that the little satellites will zoom past Mars and continue on an eternal orbit around the Sun.
"They will be out there for hundreds of thousands of years floating in space," he said.
Depending on how things go with the InSight landing, the CubeSat mission may end, or they may be deployed to pick up extra information as they travel in space.

The future of space exploration is small

Andrew Dempster, who is involved in developing CubeSats in Australia, said the MarCO mission demonstrated "you can do serious things with small satellites"
"CubeSats have been thought of as being not as valuable or as functional as big expensive satellites, maybe just for hobbyists or people who just want to get into space," Professor Dempster, of the University of New South Wales, said.
Until the MarCO mission, CubeSat technology had only been used in what is known as low Earth orbit — between 640km and 1,600km above us.
Australia currently has five CubeSats in space, including four that were deployed last year from the International Space Station.
"These early ones have been a bit of a learning exercise," Professor Dempster said.
They have enabled the science teams involved from several Australian universities to test new instruments and materials and perform science experiments such as monitoring the ionosphere.
Professor Dempster predicts the technology will be a disruptive force in the future, with companies already talking about launching constellations of small satellites into low Earth orbit to replace bigger, more expensive satellites.
And now we've proven the miniature technology can operate in deep space, they are likely to play a role in missions such as exploring asteroids for minerals, he added.
"For that to be economic, especially in the exploration phase, we're going to have to send things like CubeSats," Professor Dempster said.
Dr Clement said the advantage of the technology is it can carry a small payload, and it is low-risk in terms of cost and mass — each of the MarCO satellites only weigh about 14 kilograms.
"CubeSats really give you an option to [add extra capacity] — with relatively little investment and very little additional mass — to a flight system that is planning to travel far out into the solar system," Dr Clement said.
"I expect we will begin to see people utilise those learnings that we've gained over the last few months … in deep space all over the solar system."
For now though, the focus is on the InSight landing towards the end of this month.
"All the proof points of being able to navigate, being able to communicate, being able to survive in deep space — we've shown we can do all those things," Dr Clement said.