Nasa is set to announce which missions have been selected for the next round of its 'Discovery' Program.

The Discovery Program started in 1992 and is focused on answering questions about our solar system through low-cost missions.

Out of five mission concepts chosen in 2015, three targeted at asteroids and two at Venus, a maximum of two have been chosen to launch no later than 2021.

The results will be announced tonight at 9PM GMT (4PM ET),

Nasa is set to announce, tonight at 9PM GMT (4PM ET), which mission or missions have been selected for the next round of its 'Discovery' mission. The Discovery Program started in 1992 and is focussed on answering questions about our solar system through low-cost missions

FIVE SHORTLISTED MISSIONS - Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI). - The Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy mission (VERITAS). - Psyche, looking at the origin of planetary cores by studying the metallic asteroid. - Near Earth Object Camera (NeoCam) that would help to discover 10 times more near-Earth objects than the total number discovered to date. - Lucy that would visit the Jupiter Trojan asteroids. Advertisement

'Nasa's Discovery Program gives scientists the opportunity to dig deep into their imaginations and find innovative ways to unlock the mysteries of the solar system,' the program website says.

In 2015, Nasa announced it had narrowed down five missions as part of the Discovery selection process.

These missions were awarded $3 million (£2.4 million) each – with which scientists worked for a year to complete detailed hardware design, cost analysis, and science planning.

At the time, Nasa said it expected to choose one or two missions for flight opportunities 'as early as 2020'.

The five shortlisted missions include two targeted at Venus and three at asteroids.

The Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI), a mission to study the chemical composition of Venus' atmosphere over a 63-minute descent.

The Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI), a mission to study the chemical composition of Venus' atmosphere over a 63-minute descent. Artist's conception of DAVINCI probe descent stages

The Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy mission (VERITAS). This would provide a high-resolution, global topography and imaging of the surface of Venus – providing the first maps of deformation and the plant's surface

This would provide a better understanding of whether there are still active volcanoes on the surface of Venus, and how the surface interacts with the atmosphere.

The second mission short-listed is the Venus Emissivity, Radio Science, InSAR, Topography, and Spectroscopy mission (VERITAS).

This would provide a high-resolution, global topography and imaging of the surface of Venus – providing the first maps of deformation and the plant's surface.

Psyche is the third short-listed mission, looking at the origin of planetary cores by studying the metallic asteroid Psyche.

This asteroid appears to have survived a violent collision with another object, the consequence of which was that it stripped the outer, rocky layers of a protoplanet.

The Near Earth Object Camera (NeoCam) would help to discover 10 times more near-Earth objects than the total number discovered to date.

Finally, the Lucy mission would visit the Jupiter Trojan asteroids, an understanding of which could help us understand the history of our solar system.

Psyche is the third short-listed mission, looking at the origin of planetary cores by studying the metallic asteroid Psyche. This asteroid appears to have survived a violent collision with another object. Artist's impression of the Psyche mission, pictured

This artist concept illustrates the NEOCam space telescope, which could survey the regions of space closest to the Earth's orbit, where potentially hazardous asteroids are most likely to be found. NEOCam will use infrared light to characterize their physical properties

The Lucy mission would visit the Jupiter Trojan asteroids, an understanding of which could help us understand the history of our solar system. The asteroids of the inner Solar System and Jupiter are shown on a diagram

Members of the press have been invited to a teleconference which will be streamed live, and the public can ask questions on Twitter using the hashtag #AskNASA.

Thomas Zurbuchen, associate administrator of Nasa's Science Mission Directorate in Washington will take part in the call along with Jim Green, director of Nasa's Planetary Science Division in Washington, in addition to the Principal investigator(s) of the selected mission(s), according to Nasa.