This week, three NASA missions returned their first light data on NASA’s web page. First light is the first data sent back to earth from the satellite, proving that the equipment arrived safely into a stable orbit and all the equipment is functioning well. These three missions are diverse in purpose: the Transiting Exoplanet Survey Satellite (TESS) is taking a full survey of the sky to look for exoplanets passing in front of their stars, the Parker Solar Probe is going to study the sun closer than ever before, and Global-scale Observations of the Limb and Disk (GOLD) is inspecting the boundary between the upper atmosphere and space.
COURTESY OF NASA
TESS is the most alluring of the three, as it searches for planets which could be abodes for life. According to NASA, it will survey a total of 200,000 stars, and expects to find 20,000 planets, ranging in size from that of earth to gas giants larger than Jupiter, over the course of its two year mission. Astronomers have divided the sky into sectors for TESS to monitor. The satellite will take one image every 30 minutes for 27 days. This will allow deep learning algorithms and astronomers to analyze the images for any stars whose brightness dips periodically from one photo to another, suggesting that a planet just passed in front of its sun. This strategy is known as the “transit” method, as the telescope looks for planets in transit across their star. The James Webb Telescope, now planned to launch in March of 2021, will carefully inspect a selection of the planets that TESS finds to analyze, to see whether the planet has biosignatures or would be able to support life among other characteristics.
The Parker Solar Probe, on the other hand, has plotted a trajectory straight toward the most hostile but important environment for life in our solar system: our sun. Although we take the sun for granted, there are actually many outstanding questions about it. Over the course of seven years, the Parker Solar Probe will orbit closer and closer to the sun. In the end, it will fly incredibly close, just 4 million miles from the surface of the sun, into the edge of the corona, where temperatures can exceed one million degrees Fahrenheit. To withstand the destructive radiation and heat at this location, the probe has a special heat shield to protect its sensitive instruments. It will observe the solar wind (the source of the Northern Lights), and the heat dynamic within the layers of our home star, hopefully explaining why the outer layer is hotter than the core. This information will better our understanding of stars and catapult the field of heliophysics, the study of the sun and its effect on our solar system.
GOLD will be looking much closer to home for its research. It will focus on the uppermost part of Earth’s atmosphere, the ionosphere, where charged particles from the Earth intermingle with those from space. Contrary to popular belief, space is actually teeming with particles traveling at very high speeds. Most of the particles in our solar system are thrown off by the solar wind that the Parker Solar Probe is studying. The ionosphere, 60-400 miles above Earth’s surface interacts with these particles and deflects harmful radiation from the Earth, allowing life to flourish on the ground. The height range of the ionosphere is too high for planes and balloons and too low for satellites to inhabit. Luckily, the interactions between charged particles produce “airglow,” characteristic light emitted due to the collisions between the atmospheric molecules and space molecules. GOLD takes advantage of this glow by studying the ultraviolet light released by the interface between Earth and space from 22,000 miles above Earth’s surface. Like TESS it records a full image every half hour. GOLD’s image shows the atmosphere, or disc, over time allowing scientists to analyze how the atmosphere fluctuates.
These three missions are set to study some of the most relevant questions in astrophysics: from stars to planets to the space in between. Although space seems distant from everyday life, GOLD mission scientist Sarah Jones remarks, “Space isn’t just the home of astronauts and satellites; it affects our day-to-day lives.” The objectives of these three missions will help us to understand the relationship that Jones identifies even better.