Image copyright NASA Image caption NASA has focused its search on eight small solar system candidates since the ExoMars rover mission in 2016
Scientists in the US are calling for a rethink of planetary science strategies to better hunt for signs of alien life.
Their proposals include using satellites and jets to transmit signals to larger space probes such as orbiting telescopes.
“I think we’re going to have to try to change our paradigms in the next decade,” said astrophysicist David Grinspoon of the SETI Institute in California.
Astronomers have made some significant discoveries recently of planets that are the likely birthplace of alien life.
Mr Grinspoon and fellow physicist Vicky Kalogera of Nasa’s Ames Research Centre, and planetary scientist Simona Tumanova of the California Institute of Technology (Caltech) set out their proposals in a paper published in Nature on Saturday.
Predicting communication links
They note that current Mars missions such as the ExoMars rover have focused on areas within a tiny sphere of the Red Planet.
Some have suggested that radio transmissions from Mars may be just a few hours long, or even less, to make the planet’s high temperatures more conducive to data transmission.
Image copyright NASA Image caption The world of planetary science is changing, with smaller space probes seen as more cost-effective
“Some theories say we may only be able to detect radio signals for several hours or a day,” said Dr Tumanova.
But even a very short transmission time might be all the evidence we need, if it can be verified and taken into account, the researchers say.
As of now, the only technology capable of providing short radio bursts is very short-wave radio, something that is not suited to that time scale.
Instead, the team is proposing to develop hyperspace lasers that could “boost” a spacecraft’s ion engine, or even loft it by an interplanetary rocket.
The technology is already in use on Earth and by other spacecrafts, so is not new.
Image copyright Caltech Image caption Sending an ion engine would boost a spacecraft to higher altitudes
But Nasa does not have a space travel budget that will allow it to simply buy this system on the black market.
“Instead of coming up with this life-saving technology, we should try to tie it to a mission,” said Dr Grinspoon.
“We have to have a plan to be able to build this technology before we send it.”
This would be funded through the release of some of the money Nasa’s Planetary Science division invests every year into planetary missions.
A decision has been delayed until 2019, but NASA’s Planetary Science director Jim Green said he did not think it would be difficult to find consensus for funding such a mission.
What about life in Earth-like worlds?
There is evidence that could indicate whether alien life is abundant, if not abundant, on exoplanets.
Earlier this year, researchers announced a “revolutionary” new technology that could also support the observation of life in this area.
Researchers believed the world of Kepler 22b, which orbits its star at a distance of about 150 light years from Earth, holds an atmosphere containing atmospheric levels of carbon dioxide, methane and water that would be more suitable for life than Earth’s.
Mr Grinspoon and his team hope to observe planets orbiting stars in similar conditions to those of Earth in subsequent years, in an attempt to see whether they might be able to preserve some form of life.
“We have a capability now that’s worth exploring,” said Mr Grinspoon.
“These planets are really big enough that you have whole planets forming there. We have to fly in there, see what happens, and do what we can.”
• Watch David Grinspoon discuss the plan on the Google Science Friday podcast