The first dual-satellite mission to another planet, NASA’s ESCAPADE (Escape and Plasma Acceleration and Dynamics Explorers), is scheduled for launch no earlier than Sunday, Nov. 9, from Cape Canaveral, Florida. The two identical spacecraft are managed and operated by the University of California, Berkeley, and will fly in formation to map the magnetic fields, upper atmosphere and ionosphere of Mars in 3D, providing the first stereo view of the Red Planet’s unique near-space environment.
What they find will help scientists understand how and when Mars lost its atmosphere and provide key information about conditions on the planet that could affect people who land or settle on Mars.
“Understanding how the ionosphere varies will be a really important part of understanding how to correct the distortions in radio signals that we will need to communicate with each other and to navigate on Mars,” said ESCAPADE principal investigator Robert Lillis of UC Berkeley’s Space Sciences Laboratory (SSL).
The satellite pair, which will arrive at Mars in 2027, have been nicknamed Blue and Gold in honor of UC Berkeley’s school colors. They will be operated from SSL’s mission operations center (MOC) in the hills above the Berkeley campus. The science instruments, deployable booms and data processing computers were built by UC Berkeley and its partners, while the ESCAPADE spacecraft were built by Rocket Lab USA, headquartered in Long Beach, California. The NASA mission will be carried into space by a New Glenn rocket built by Blue Origin, headquartered in Kent, Washington.
Mapping the planet’s magnetic fields and their response to space weather is important because Mars has neither a global magnetic field like Earth’s, nor a thick atmosphere to shield the surface from damaging solar storms. As a result, anyone living on the surface will have to protect themselves from the high-energy particle radiation that damages DNA, increasing the risk of cancer. A background radiation level from our Milky Way galaxy is always present on Mars, Lillis said, but last year NASA’s Curiosity rover documented an intense solar storm that delivered in one day the equivalent of 100 days of this “normal” background.
“We will be making the space weather measurements we need to understand the system well enough to forecast solar storms whose radiation could harm astronauts on the surface of Mars or in orbit,” Lillis said.
Aside from its main missions, ESCAPADE will also pioneer a new route or trajectory to Mars. Typically, missions to Mars are launched within a tight window — just a few weeks long every 26 months — that allows the spacecraft to take the most fuel-efficient route: an elliptical path that allows the spacecraft to exit Earth’s orbit and insert into Mars’ orbit at just the right time to catch the Red Planet as it hurtles by. Trajectories typically take between seven and 11 months. All Mars missions up to now have used this route, called a Hohmann Transfer, which has restricted launches to this once-every-two-years alignment between Earth and Mars.
ESCAPADE will instead head first to a Lagrange point — a place where the gravitational pull of the sun and Earth are equal — and loop around it in a lazy, 12-month kidney bean-shaped orbit that eventually brings it back toward Earth in early November 2026. At its closest approach, ESCAPADE will fire its engines to slingshot around Earth and head out to meet Mars during its biannual alignment with Earth.
If humans plan to settle Mars in the future, hundreds to thousands of crewed and uncrewed ships will need to head out during every alignment, Lillis said. Since Earth has a limited number of launch pads and weather and technical delays are common, the flexible trajectory ESCAPADE will pioneer could allow all these spacecraft to launch over many months, “queueing up” before zipping off to Mars during the planetary alignment.
“Can we launch to Mars when the planets are not aligned? ESCAPADE is paving the way for that,” said Jeffrey Parker of Advanced Space LLC, one of NASA’s partners on ESCAPADE, at a conference earlier this year.
Science goals
Experiments built at UC Berkeley have been going to Mars for nearly 60 years, unveiling its atmosphere, magnetic fields and space weather to understand what shaped the planet we see today. Berkeley built instruments for NASA’s Mars Global Surveyor mission, which launched in 1996 and discovered that Mars lost its global magnetic field about 4 billion years ago. Berkeley now has instruments on two ongoing missions — NASA’s MAVEN, launched in 2013, and the Emirates Mars Mission Hope probe, launched in 2020 — that are still monitoring Mars’ atmosphere, and discovering new kinds of aurora.
These missions have shown that, while Mars lacks a global magnetic field like Earth’s, it does have localized magnetic fields caused by its strongly magnetized crust. These “crustal fields” are the remnant of a long-gone global magnetic field that magnetized rocks as they cooled or were altered by water.
“Mars has this patchy crustal magnetism that results in magnetic fields that are locally strong though generally far weaker than Earth’s field,” Lillis said. “They’re effective at pushing the solar wind away up to 1,500 km away from the surface.”
As the newest Berkeley-led mission, ESCAPADE’s two probes will fly in different orbits around the planet, providing a 3D view of how the Martian atmosphere responds to changes in the solar wind, a million-mile-per-hour, gusty stream of charged particles from the sun. The goal is to understand better how the solar wind energizes the particles and helps them escape into space. The escape of water and other atmospheric gases over the past 4 billion years has led to a thin, wispy atmosphere, less than 1% the density of Earth’s.
“To understand how the solar wind drives different kinds of atmospheric escape is a key piece of the puzzle of the climate evolution of Mars. ESCAPADE gives us what you might call a stereo perspective — two different vantage points simultaneously,” Lillis said.
The data could help determine what happened to the water that once filled lakes and rivers on Mars, at least episodically, up until 2 billion years ago, and whether it’s still available underground to be tapped by future Martian colonists.
“The geological evidence shows that Mars once had water on it, and in order to keep the water, you need a thick atmosphere,” said space physicist Shaoxui Xu, deputy principal investigator for the mission. “So we know that there was a thick enough atmosphere on Mars once upon a time, but now it is very tenuous. There are only two ways for atmosphere to leave — either go into the ground or escape to space, and there are a lot of studies showing that escape has been a very significant contributor to the evolution of the atmosphere.”
Understanding how the solar wind affects the upper atmosphere, or ionosphere, also has implications for communications on the planet surface, since bouncing radio signals off the ionosphere allows communication over the horizon.
A new way of doing things
Lillis and colleagues have been working on ESCAPADE since 2016, when NASA provided seed money for a concept study. That resulted in the proposal to NASA’s SIMPLEx program, or Small Innovative Missions for Planetary Exploration program, in 2018, which aimed to fund missions for a fraction of the cost of typical missions. ESCAPADE was selected for funding in 2019. While SSL engineers designed and built the experiments, Rocket Lab USA, a global leader in launch services and space systems, designed and built the spacecraft to carry the instruments and integrated and tested them at the company’s complex in Long Beach. The cost to deliver the spacecraft to the launchpad in 2024 was $49 million.
“ESCAPADE represents a new way of doing things, with much lower cost, more commercial involvement, and a somewhat higher risk tolerance,” Lillis said. “The reliability of individual components and subsystems has improved, so it’s possible to send two spacecraft to Mars for roughly one-tenth of what it would have cost 10 or 15 years ago.”
The mission was originally scheduled to launch during a planetary alignment window in the fall of 2024 on board the inaugural launch of the New Glenn rocket. When that was delayed beyond the brief planetary alignment window, ESCAPADE was rescheduled for the second flight of New Glenn this fall and a totally new trajectory to Mars.
Once the satellites arrive at Mars, they will take about seven months to settle into lower orbits that are synchronized “so that they essentially are in the same orbit, following each other like a pair of pearls on a string,” Lillis said.
“That’s important scientifically because it lets us monitor the short timescale variability of the system. We don’t know what it is right now because the missions that have gone before, like MAVEN and Europe’s Mars Express, have had to wait until the following orbit, about four or five hours later, to see what conditions are like in a particular region,” Lillis said. “When we have two spacecraft crossing those regions in quick succession, we can monitor how those regions vary on timescales as short as two minutes and up to 30 minutes. Before we had to wait for several hours. So this will allow us to really make measurements we’ve never made before, and to characterize a very dynamic system in a way we couldn’t characterize it before.”
The UC Berkeley instruments onboard include two electrostatic analyzers to measure the flux and energies of particles — both ionized atoms and electrons — that are escaping Mars.
“We’ll know which direction (the particles) are going and what energies they have, which tells us if they’re coming back to Mars or if they are able to leave Mars,” said Gwen Hanley, a member of the science team at SSL.
“We can learn a lot about the way that particles are flowing and the electric fields that accelerate ions and electrons and the local Mars environment,” added Phyllis Whittlesey, science lead for the electron electrostatic analyzer.
Scientists at NASA’s Goddard Space Flight Center contributed a magnetic field detector, while researchers at Florida’s Embry-Riddle Aeronautical University built a device to measure the charged particles, or plasma, around the spacecraft. An onboard camera from Northern Arizona University will photograph dust and the planet’s aurora.
For all his interest in Mars, Lillis admits that he would not want to visit. With extremely low atmospheric pressure, your blood would boil without a pressure suit, he said. And people would likely have to live and work underground much of the day to minimize exposure to the cosmic radiation hitting the surface.
“It is definitely going to be a challenge to establish a human settlement on Mars,” he said. “But, you know, humans are tenacious, right?”
