For a few weeks now, data from two rovers has been flowing into my page The Watched Planet. Perseverance is driving along the rim of Jezero Crater. Curiosity is climbing through the layered rock of Gale Crater. Every day a new image reaches Earth. It is a beautiful sight, and it is deceptive.

Mars has almost as much surface as all of Earth's continents combined. Everything we know about it up close comes from about ten landing sites. Together, the two rovers have covered less than a hundred kilometers. The rest of the planet is known only from orbit.

This is the world whose settlement we have been discussing for years.

What We Actually Measure

Even the view from above has more gaps than the images suggest. The sharpest camera in Mars orbit has been working since 2006. It has taken more than 70,000 images. Together they show only a few percent of the surface, much of it twice.

Below the surface, our knowledge grows thinner still. Ice is the most important resource for any settlement. From orbit it can be detected reliably down to about thirty centimeters. Below that, the measurement quickly loses its precision. An analysis published this summer shows that the uncertainty is greatest exactly where people would most like to land.

No one measures quakes anymore. The InSight lander listened into the planet for four years. In December 2022 it fell silent. Since then, Mars has been seismically quiet to us. The next seismometers are headed for the Moon and for Saturn's moon Titan. None is planned for Mars.

We know the weather from only a few points. In the entire history of spaceflight, eight missions have returned weather data from the Martian surface, each for a limited time. Dust storms can shroud the whole planet for months. With so few stations, they can hardly be forecast.

Radiation is measured by a single instrument in a single place, aboard Curiosity. The most dangerous events for humans are the particle storms that follow solar eruptions. On the surface, the instrument has so far captured almost none of them.

A Year of Losses

2026 has made this situation worse. In June, NASA declared its MAVEN orbiter lost. Of its spacecraft in Mars orbit, two remain: Odyssey, launched in 2001, and the Mars Reconnaissance Orbiter, launched in 2005. Both have been working far beyond their planned lifetimes for years. The younger one's spectrometer stopped back in 2023. The 2026 budget request even proposed shutting Odyssey down. Only Congress saved it.

Mars Sample Return has been cancelled. Around 2.5 billion dollars had been spent by then. The sealed tubes Perseverance collected are still lying in the dust of Jezero Crater. China plans to retrieve its own samples with Tianwen-3 in 2028.

In February, SpaceX changed course. This autumn's launch window will pass without a Starship. The Moon now comes first.

What is being newly built is mainly a line of communication. Blue Origin will deliver a relay satellite to NASA by the end of 2028. From 2030 it is meant to pass data between Mars and Earth. That matters. But a radio relay measures nothing. We are building the road before we have the map.

Eighteen Thousand Against a Few Dozen

One comparison shows the scale. Around 18,000 active satellites circle Earth today. They watch clouds, oceans, harvests and every movement of the atmosphere. Beyond Earth orbit, only a few dozen spacecraft are at work. They are spread across the Sun, the Moon, Mars, Jupiter and the edge of the solar system.

So we measure our own planet a thousandfold. The space we intend to move into, we observe with a handful of instruments. Most of them are old.

No shipping company would send a vessel along a route whose weather it knows from only two buoys. For the settlement of a planet, that is exactly what we are planning.

From Project to Service

I see the reason less as a question of money than as a question of mindset. Spaceflight plans in missions. A probe is built, flies and answers its questions. Then it falls silent. Until the next mission is approved, a gap opens. InSight and MAVEN show what that gap looks like.

On Earth, we abandoned this way of thinking about weather long ago. A weather satellite is replaced before the old one fails. No one would accept a gap in the forecast, because people depend on it.

The solar system needs the same step. Research projects have to become a measurement service that never switches off. Fixed points collect data continuously and send it to Earth. When a station ages, its successor is already in place. That way we can prepare instead of hope.

Where the First Fixed Points Must Stand

The network does not begin at Mars. It begins at the Sun. That is where the greatest danger comes from for anyone traveling between the planets. Today we observe it almost entirely from Earth's direction. One sentinel sits about one and a half million kilometers ahead of us, at the Lagrange point L1. Depending on a storm's speed, it gives between twelve minutes and an hour of warning before the storm reaches Earth. For a ship on its way to Mars, that is not enough.

The first new point therefore lies sixty degrees behind Earth on its orbit, at the Lagrange point L5. From there you can see the side of the Sun that will only turn toward us days later. A storm forming there would be known before it becomes a threat. Its counterpart, L4, sits sixty degrees ahead of Earth. It looks at the side of the Sun that is just turning away. That is often the side that faces the route to Mars.

These two points solve a second problem as well. Every 780 days, Mars disappears behind the Sun as seen from Earth. For about two weeks, no radio contact is possible. For robots, that is a pause. For a settlement, it would be a stretch of time with no connection to Earth. A relay station at L4 or L5 can transmit around the Sun. The early warning post becomes a bridge.

At Mars itself, the first need is a sentinel on the sunward side, about a million kilometers ahead of the planet. It sees every storm before it hits Mars. Without it, radiation warnings for people there remain blind.

Closer to the planet comes the weather service. At an altitude of 17,000 kilometers, a station circles exactly as fast as Mars rotates. It therefore hovers over the same spot. From there it overlooks almost the entire side facing it. Three such stations are enough to keep the whole planet in view at all times, except for the poles. They are complemented by a radar on an orbit over the poles. Only such an orbit passes over every point on the surface. The radar finds ice at the depth where building would happen.

On the ground, distribution decides everything. Four to six seismometers must stand as far apart as possible so they can locate quakes from every direction. One belongs at Cerberus Fossae, where many of the quakes InSight heard came from. Others belong at the volcanoes of the Tharsis region, at the rim of Valles Marineris and in the southern highlands. Two stand where landing sites are being discussed today, in Arcadia Planitia and in Deuteronilus Mensae. Each of these stations also measures weather and radiation.

The Moon remains the test bench. A station at its south pole and one on its far side can prove every technology before it flies to Mars.

Together that makes twenty to thirty stations. They form the framework. From it, the thousand probes grow over time. Every station is replaced before it fails. Where people arrive, the network becomes denser.

What It Costs

It has also become more affordable than many assume. At the end of 2025, NASA sent two small probes to Mars. The ESCAPADE mission cost less than 80 million dollars. That is about a tenth of a classic Mars mission. Rocket Lab built the probes, Blue Origin launched them.

At that price, a thousand probes would come to roughly 40 billion dollars. Spread over twenty years, that is about two billion a year.

Harder than the sum is reliability. A measurement service cannot depend on whether a single budget request cancels a working spacecraft. Odyssey showed this year how close that can come. A network meant to protect people needs many shoulders. States, companies, foundations and citizens can pay for it together. Its data must be open to everyone who sets out.

First See, Then Go

When people talk about the future of humanity, the word galaxy comes up quickly. It remains the horizon. The task of this generation lies closer. We have to come to know our own solar system as well as our own Earth before the first people live in it.

Every measurement we collect today is an advance payment for someone who, decades from now, steps out of an airlock onto Mars. They will want to know whether the ground beneath them is shaking. They will want to know whether a storm is coming. And they will rely on the ice being where the map promises.

These answers will not come from a single mission. They will come only if we start measuring now and never stop.

| The Planet Futures Organization, the first multiplanetary NGO.

Homepage: https://planet-futures.org