Homework 3

Release Date:: 2024/03/11
Due Date:: 2024/03/18 23:59:59
Topic:: Planetary Mission
Disclosure:: This homework is based on a hypothetical setting and does not represent any real mission endorsed by NASA or any other space agency.

Selection of Planetary Mission instruments

Description:

NASA is planning a mission to observe Sedna, a dwarf planet that resides in the outermost region of the Solar System. Sedna has a highly elliptical orbit that takes it from 76 AU at its closest approach to the Sun to 937 AU at its farthest. At 2076, Sedna will be at its closest approach to the Sun. The next perihelion will be in 11400 years.

The mission will be a New Frontiers class mission, meaning that it will be a medium-sized mission with a cost cap of about 1 billion dollars. The mission will be an orbital mission that can continuously observe the planet for a long period of time. The launch window has been decided and the orbital trajectory has been planned.

The spacecraft will carry a set of instruments to observe the planet Sedna, including its atmosphere, surface and interior. The selection of the instruments is a critical part of the mission planning. The instruments should be able to observe the planet from orbit and should be able to operate in the harsh environment of the outer Solar System.

The suite of instruments onboard the spacecraft should significantly contribute to the understanding of the big science questions related to planets. Moreover, the mission should have a strong public engagement and education component to inspire the next generation of scientists and engineers.

You serve on the selection committee for the mission instruments. You have been tasked with selecting the instruments that will be carried on the spacecraft. Note that a significant part of the mission budget will be allocated to radiogenic power sources and thermal control systems to keep the instruments operational in the cold outer Solar System. The total budget for the instruments is minimal and should be carefully allocated to maximize the scientific return of the mission.

Based on the above description, answer the following questions:

1. (5’) The big question, Part I

First, you would need to explain the scientific objectives of the mission to your other committee members. What are the big science questions that the mission aims to address?

Re-visit the slides in Lecture 3, Planetary Formation II, on the N-body simulations of the evolution of the Solar System. This is called the “Nice Model” and it is a good starting point to understand the big science questions related to how Sedna formed and how it might end up in its current orbit. It is named the “Nice Model” because it was first proposed by a group of scientists in Nice, France.

Read a Nature article on the “Nice Model” here and write a brief paragraph that summarizes the key findings of the “Nice Model”.

2. (5’) The big question, Part II

Sedna was not alone in the outer Solar System. There are about a dozen other objects found in the same region of the Solar System as Sedna, between the Kuiper Belt and the Oort Cloud. No one knows how these objects ended up in their current orbits. Some theories suggest that these objects were scattered to their current orbits by the mechanism similar to the “Nice Model”, while others suggest that these objects are captured from other stars passing by.

Using the Hubble Space Telescope, astronomers found that Sedna has a reddish color, which is similar to the color of Pluto and Charon. This suggests that Sedna might have formed in the Kuiper Belt.

Survey the instruments onboard the New Horizons mission to Pluto and write a brief paragraph that explains what were the instruments carried on the spacecraft and what were the key findings of the mission.

3. (5’) Selecting a remote sensing instrument

You received three remote sensing instrument proposals. The first proposal is for a high-resolution infrared spectrometer that claims to quantitatively measure the composition of the atmosphere and the surface of Sedna over a limited spectral range.

The second proposal is for a low-resolution but broad-band infrared camera that can survey the entire infrared spectrum of Sedna. Getting a quantitative measurement of the composition is a challenge.

The third proposal is a low-cost visible-light camera that can take high-resolution images of the surface of Sedna. The camera can take images in a few filters to make a color composite image of the surface.

You cannot afford to carry all three instruments on the spacecraft. You need to select two of the three instruments. Which two instruments would you select and why?

There is a correct answer to this question, based on previous mission instrument selection results in similar situations. You need to justify your selection based on the information provided in this homework.

4. (5’) Selecting an in-situ measurement instrument

You received two in-situ measurement instrument proposals. The first proposal is an magnetometer that can measure the magnetic field of Sedna. The second proposal is a lander that can land on the surface of Sedna and measure the composition of the surface. Provide compelling arguments for selecting both instruments or only one of the two instruments.