Home/Companies/Relativity Space vs Sierra Space

Company pair · Aerospace & Defense

Relativity Space vs Sierra Space: Valuation, Funding, Trajectory

Aerospace & Defense Both private US-headquartered No Canborsa market

This comparison puts Relativity Space next to Sierra Space within aerospace-defense on size, funding and trajectory.

On this pageSide by side Valuation marks What each discloses Verdict FAQ

Relativity SpacePRIVATE · US

Sierra SpacePRIVATE · US

Last valuation$4.2B$8B

Basis Basis undisclosed Post-money

As ofJun 2021Mar 2026

Founded20152021

Employees≈2,000≈2,000

On CanborsaNo marketNo market

At a glance

$4.2B

Relativity SpaceSeries E · Jun 2021

$8B

Sierra SpacePost-money, Series C · Mar 2026

A valuation basis is undisclosed — no ratio is scored

Gap

0 of 2

On CanborsaNeither company has a market

Head-to-head · field by field

Relativity Space vs Sierra Space — side by side

Field

Relativity SpacePRIVATE · FOUNDED 2015

Sierra SpacePRIVATE · FOUNDED 2021

Last valuation

$4.2B Basis undisclosed

$8B Post-money

Valuation date

8 Jun 2021

1 Mar 2026

Latest round

Series E

Series C

Round size

$650M

$550M

Round lead

Fidelity Investments

LuminArx Capital Management

Named investors

Fidelity Investments Baillie Gifford BlackRock BOND

LuminArx Capital Management General Atlantic Coatue Moore Strategic Ventures

Founded

2015

2021

Employees (est.)

≈2,000

Sector & HQ

Aerospace manufacturing / commercial spaceflight · 🇺🇸 US

Aerospace / commercial spaceflight and defence · 🇺🇸 US

Status & market

Private — no Canborsa market

Valuation · both companies on one scale

Valuation marks

Each bar is the last disclosed mark — $4.2B for Relativity Space (basis undisclosed, Jun 2021) and $8B for Sierra Space (post-money, Mar 2026).

Relativity Space

$4.2Bbasis undisclosed · Jun 2021

Sierra Space

$8BPost-money · Mar 2026

RELATIVITY SPACE · $4.2B · JUN 2021SIERRA SPACE · $8B · MAR 2026

Relativity Space vs Sierra Space · what each company discloses

What each company discloses, and what it leaves out

Relativity SpacePRIVATEAerospace & Defense · US · 2015

+Last disclosed mark $4.2B — basis undisclosed, Jun 2021.

+Founded 2015 .

+≈2,000 employees.

+Latest round: Series E, $650M raised, led by Fidelity Investments.

Sierra SpacePRIVATEAerospace & Defense · US · 2021

+Last disclosed mark $8B — post-money, Mar 2026.

+Founded 2021 .

+≈2,000 employees.

+Latest round: Series C, $550M raised, led by LuminArx Capital Management.

Verdict

Verdict

The $4.2B tells you…

The $8B tells you…

What an investor paid for newly issued shares — a primary round, priced post-money.

How much capital arrived with it:$550M, led by LuminArx Capital Management in Mar 2026.

A dated print: it moves only when a newer round is announced.

At least one valuation basis is undisclosed, so the two numbers stay side by side, each with its own chip, and no ratio is scored. Both are private: there is no public quote and no Canborsa market on either name.

Frequently asked questions

What sector is Relativity Space in compared to Sierra Space?›

Relativity Space operates in Aerospace manufacturing / commercial spaceflight, and Sierra Space operates in Aerospace / commercial spaceflight and defence.

What is Relativity Space's valuation versus Sierra Space's?›

Relativity Space is valued at $4.2B, and Sierra Space at $8B.

Who are the lead investors in Relativity Space and Sierra Space?›

Relativity Space's lead investors include Fidelity Investments, and Sierra Space's include LuminArx Capital Management.

What's the location of Relativity Space versus Sierra Space?›

Relativity Space is based in Long Beach, California, and Sierra Space is based in Louisville, Colorado.