A few weeks ago, a group of scientists from the California Institute of Technology announced that they had succeeded in transmitting energy to Earth from an orbiting satellite. It wasn’t much energy, but it showed it was possible. Eventually, we will be able to transmit energy from solar satellites to Earth, make solar energy available almost everywhere, and help fight climate change. But there is another potential application: powering surface probes on Venus.

Everyone knows Venus. It killed several landers due to the extreme heat and overwhelming atmospheric pressure. The former Soviet Union sent a series of probes to the surface of the planet, many of which failed. The most successful was Venera 13, which lasted just over two hours at 457 °C (855 °F) and was subjected to 9.0 MPa (89 standard atmospheres).

Despite Venus 13’s brief but significant success, the planet has kept its secrets, and we return to its surface to unravel its secrets. That’s why NASA wants to send a vehicle to the surface as part of the DAVINCI+ (Investigation of Deep Atmosphere Venus Noble Gases, Chemistry and Imaging) mission.

But the question is how to secure a landing on Venus’ unique, treacherous surface, assuming we can create a surface that doesn’t easily succumb to Venus’ adverse conditions. Conventional methods—solar power, batteries, radioisotope thermoelectric generators—are not up to the task. This is evidenced by a new study published in the journal “The possibility of energy radiation through the atmosphere of Venus.” Acta Astronautica. Eric Brandon, co-author of the Jet Propulsion Lab.

“State-of-the-art space energy technologies, including solar cells, batteries, and radioisotope thermoelectric generators, cannot operate on the surface of Venus, limited to high temperatures, high pressures, and corrosive environment,” the authors explain.

Venus is closer to the Sun, but its thick atmosphere means that not much solar radiation reaches the surface. About 75% of the solar energy is reflected by the clouds of Venus, and only about 2.5% of the solar flux falling into the upper atmosphere reaches the surface. Extreme solar energy above the clouds. Venus receives twice as much solar radiation at the top of its atmosphere as it does at the top of Earth’s atmosphere.

Can this abundant energy be used by solar collectors above the clouds and then channeled to the terrain vehicle/rover? It would have to go through a lot of thick clouds. “The feasibility of this approach and other related task concepts are discussed in this document from the perspective of atmospheric absorption and dispersion of radiated energy,” the document states.

The transfer of energy from one place to another is called wireless energy (or power) transfer. There are two types: near field and far field. Near field is short range power transmission similar to the type used in charging panels for mobile devices. Far-field energy transfer is also called energy radiation and uses microwaves or lasers to transfer energy from the generator to the receiver.

One of the challenges of transferring energy from an orbiting solar collector to a land vehicle is the complications in the stationary orbit of Venus. The planet rotates so slowly that the stationary orbit is very far from the planet, which makes the orbit unstable. One way or another, the solar collector should be closer to the planet. Above the upper clouds, at about 60 or 70 km, the collector will receive essentially all available sunlight. Mission design may need to keep a picker or a group of pickers at the correct altitude and position.

An alternative solution is to transfer some power to the lander on each orbit, which may be sufficient. “Hundreds of watt-hours (watt-hours) of energy can be produced during several orbital passes of the lander,” the authors explain.

But these are bigger issues of the overall task architecture. This research shows that there are solutions to this problem. In this study, the authors focus on how to radiate and receive energy that is not fully understood. “However, if a suitable platform and mission architecture can be developed and implemented, no comprehensive study of power transmission capabilities at appropriate wavelengths has been done to date,” the authors write.

The problem is that Venus’ atmosphere is dense and contains chemicals that block microwave radiation. CO concentrations are a special issue_2.

Lasers may be a better option. Despite the problems in a dense atmosphere, there are certain “frequency windows” in the atmosphere that can allow strong radiation from lasers. “On Venus, despite the continuous cloud cover, energetic radiation from laser sources may be intuitively possible given that there are certain optical/infrared ‘windows’ in Venus’ atmosphere that are not accessible by microwave radiation,” the authors write.

Lasers also have other advantages over microwaves, such as less beam spread. This means that the receiving antennas do not have to be very large. A one-meter receiver may suffice, and it won’t be so bulky that it interferes too much with the landing design.

Although solar energy is abundant in Venus’ upper atmosphere, transmitting it to the entire atmosphere may not be the best approach. Instead, a balloon or other vehicle could be placed near the middle of the atmosphere. There it will receive as much solar energy as possible and will only need to exchange energy through part of the atmosphere.

Studies show that 47km altitude matters. There is a lower cloud at this altitude, and the energy radiated below it is subject to less scattering. It also shows that from 47 km, the highest transmittance is at 1022 nanometers, and about 20% of the radiated energy will reach the ground vehicle.

“These calculations show a reasonable approximation to the energetic radiation on Venus using transmission from an aerial platform operating close to the cloud base,” the authors write.

But is the technology there for that? The document does not mention what kind of vehicle or platform can be used at an altitude of 47 km. They focus on the radiation power itself and if calculations show that it is possible. But they also talk about current laser technology and whether it’s fit for the task.

According to the researchers, we don’t have the right type of laser yet.

However, researchers are busy developing them. Ytterbium doped fiber lasers (YDFLs) operating in the near infrared (NIR) range and capable of operating at high power are under development. Unfortunately, they do not operate at the ideal wavelength for use on Venus: 1022. Instead, they are limited to two other ranges: 970-980 nm and 1030-1100 nm. But lasers are the subject of intense interest from various researchers around the world, and progress is steady.

The task of keeping any lifting platform stable and in the correct position is critical to any power radiation mission. But researchers are already working on balloons and other flying platforms for use on Venus. The authors are confident that, assuming they can be developed, the powerful radiation scenario will stand up to the challenge and create successful missions to the surface of Venus.

“Furthermore, while there are engineering and design challenges associated with the control and guidance of such an aircraft platform used for energy radiation and overall temperature control, this analysis demonstrates that these optical windows can be used to provide sufficient power levels for the mission to be directed to the surface of Venus. “

We need to better understand Venus’ atmosphere before a particular system can be designed. DAVİNCİ+ has three main science goals and one of them is to understand the atmosphere that circulates in it. Their findings will help scientists understand what obstacles they face in radiating power to the planet’s surface. If this can be done reliably, Venus will be open to exploration. Source