Full-Time

Spacecraft Thermal Engineer

Posted on 7/15/2025

Millennium Space Systems

Millennium Space Systems

501-1,000 employees

Delivers national-security space missions and constellations

Compensation Overview

$69.7k - $102.5k/yr

No H1B Sponsorship

El Segundo, CA, USA

In Person

US Top Secret Clearance Required

Category
Aerospace Engineering (7)
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Requirements
  • Bachelor’s degree in Mechanical Engineering, Aerospace Engineering, Physics, or other relevant fields
  • Experience in the design, development, analysis, implementation, testing, and/or operation of spacecraft thermal systems or other related complex thermal systems
  • Proficiency with thermal analysis tools (e.g. Thermal Desktop, SINDA/FLUINT)
Responsibilities
  • Perform spacecraft thermal design and analyses at the board, component, subsystem, and system level
  • Develop systems and spacecraft element thermal models to predict thermal loads, impacts, and temperature margins to support system design
  • Brief design and analysis materials to program managers, customers, and/or sponsors
  • Identify all materials, processes, and facilities to achieve a qualified spacecraft thermal design and operation
  • Support thermal verification testing on spacecraft systems and components including test design, test conduct, data reduction, analysis, and reporting
  • Assist in proposal and business development efforts
  • Potential to cross-train with MLI team for hands-on support
Desired Qualifications
  • Active TS/SCI clearance
Millennium Space Systems

Millennium Space Systems

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Millennium Space Systems provides space systems for national security, delivering missile-warning and other space missions by rapidly creating affordable prototypes and satellite constellations across different orbits. Its products are designed to work correctly the first time, with an emphasis on speed to meet customer needs. The company differentiates itself by offering fast, cost-effective prototype-and-constellation solutions rather than long, expensive development cycles, focusing on reliable performance for critical space missions. The goal is to enable secure, rapid, and dependable space capabilities for national security customers.

Company Size

501-1,000

Company Stage

N/A

Total Funding

N/A

Headquarters

El Segundo, California

Founded

2001

Simplify Jobs

Simplify's Take

What believers are saying

  • Targeting 26 satellite deliveries in 2026, up from 4 in 2025 via El Segundo investments.
  • Tony Gingiss appointed CEO December 9, 2024, drives Boeing-Millennium integration.
  • Delivered TRACERS satellites to Vandenberg June 16, 2025 for NASA mission.

What critics are saying

  • Production fails 550% ramp to 26 satellites in 2026, slips schedules 6-12 months.
  • Resolute design delays past 2026 bid-ready, loses to Relativity Space.
  • FOO Fighter fails 2027-2028 testing, Space Development Agency terminates $414M contract.

What makes Millennium Space Systems unique

  • Resolute platform fills 2-4 kW gap between Millennium small sats and Boeing large sats.
  • FOO Fighter delivers fire-control sensing for hypersonic missile tracking in LEO.
  • Secured spot on Space Force’s $1.84B RG-XX Andromeda contract for GEO reconnaissance.

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Benefits

Professional Development Budget

401(k) Company Match

Remote Work Options

Paid Vacation

Paid Sick Leave

Paid Holidays

Hybrid Work Options

Mental Health Support

Wellness Program

Company News

PR Newswire
Jun 16th, 2025
Millennium Space Systems Delivers Pair Of Space Vehicles To Launch Site For Nasa'S Tracers Mission

EL SEGUNDO, Calif., June 16, 2025 /PRNewswire/ -- Millennium Space Systems, a Boeing Company, delivered two space vehicles for NASA's Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) mission to Vandenberg Space Force Base Friday, marking a key milestone in preparation for launch later this year

Envision
Apr 9th, 2025
Boeing's bet: supercharge satellite production

When Envision Employment Services Incorporated acquired Millennium in 2018, it built prototypes and delivered one or two satellites a year.

Stock Titan
Dec 16th, 2024
Millennium Space Systems Names Tony Gingiss as CEO

Millennium Space Systems, a Boeing Company [NYSE: BA], has appointed Tony Gingiss as its new CEO effective December 9, 2024.

Military News
Oct 28th, 2024
U.S. Enhances Early Warning System with New Satellite Batch for Epoch Program

Millennium Space Systems signed the initial contract to deliver the first six satellites for MTC Epoch 1 in 2023.

SpaceNews
Aug 29th, 2024
Firefly names space industry veteran Jason Kim as new CEO

Kim joins Firefly from Millennium Space, a Boeing subsidiary specializing in small satellites primarily for U.S. government agencies, where he served as CEO.

INACTIVE