President Donald Trump signed a massive $738billion Defense bill Friday – which will officially establish the Space Force.

'With my signature today you will witness the birth of the Space Force,' he said. 'And that will be now officially the sixth branch of the United States armed forces.'

He signed the legislation at Joint Base Andrews - which he dubbed 'America's Airfield' as it houses Air Force One - before he departed to Mar-a-Lago for the Christmas holiday.

As part of the 2020 National Defense Authorization Act, the US Air Force Space Command, which initially debuted in 1982, was rebranded the United States Space Force, effective immediately.

The 16,000 active duty airmen and civilians who served in the Air Force Space Command up until the moment the bill was signed, are now part of the newly-minted Space Force.

However, all those personnel would technically remain under the US Air Force's wing - and not become members of the Space Force - for the moment, military officials told CNN.

President Trump is photographed signing a giant defense spending bill that officially ushers in his Space Force

President Trump (right) shakes hands with Gen. Jay Raymond (left), the new commander of Space Force, who he introduced at the event

Gen. John Raymond, commander of US Space Command and Air Force Space Command, told reporters at the Pentagon Friday that: 'We want to build this service to be lean and agile, we're going to rely very heavily support functions from the Air Force.'

An Air Force source told the news network that an estimated 5,000 to 6,000 of the 16,000 airmen and civilians now working in the Space Force will be transferred over to the Space Force eventually.

The service members who focus on space - so-called 'space operators' - will be transferred into Space Force on a voluntary basis.

It's also expected that some airmen with specializations in intelligence, engineering and acquisition will also be transferred over to the Space Force down the line.

As many as 15,000 personnel could wind up being moved from the Air Force command to the Space Force in time, including people from units that are outside Space Force's new command.

Despite being assigned to work on the Space Force, support personnel, such as security officers and civil engineers, would remain under Air Force employ.

In addition to personnel, the Air Force will be responsible for providing the majority of Space Force's infrastructure, including officer training and recruitment, which will supposedly help eliminate additional bureaucracy.

President Trump boasted that the defense spending bill was the biggest ever - and remarked that it was $738 billion - 'that's with a B!'

President Trump's family members and the vice president and his wife huddle behind the president as he signs a giant defense bill into law Friday

President Trump speaks at Joint Base Andrews Friday. The base houses his Air Force One planes

Until further notice, Space Force personnel will continue to wear Air Force uniforms and adhere to the branch's fitness programs, personnel system and other practices, according to Air Force Times.

While only airmen are eligible to be part of the Space Force now, per Congress, the Defense Department said that its goal is to be able to transfer over Army and Navy personnel who are involved with space-related duties.

The plan is to consolidate space operators in the new military branch, Deputy Assistant Secretary of Defense for Space Policy Stephen Kitay said, according to Defense News.

Despite the eventual influx of personnel, the Space Force would still be the smallest branch of the military - in comparison, the Air Force has more than 300,000 active personnel, while the US Army has 1.3million active personnel.

The Space Force's anticipated personnel number would even be eclipsed by the US Coast Guard's 56,000 active personnel.

The military said the reason for the smaller number of Space Force servicemen is due to the fact that 'The Space Force won't be measured by the number of people unlike for instance the Marine Corps, which is really a labor-intensive service,' Air Force Secretary Barbara Barrett told reporters Friday, according to CNN.

Barrett, who now oversees the Space Force in addition to the Air Force, also told reporters that 'Space Force is much more measured by the technology and the capabilities.'

As an example, Barrett noted that only 40 airmen are needed to oversee the about two dozen orbiting satellites that make up the Global Positioning System (GPS), which is used by both the military and civilians on a daily basis.

Aside from splintering off personnel to the Space Force, the Air Force expects to rename some of its 'principal' bases - which already house Air Force Space Command units - as 'Space Bases' in the upcoming months.

Among the potential bases to be renamed could be Colorado's Peterson Air Force Base and California's Vandenberg Air Base, Raymond said Friday.

Peterson is the now-renamed Air Force Space Command's home base and Vandenberg, a space and missile-testing facility, houses the Air Force's 30th Space Wing.

First lady Melania Trump (left) and President Trump (right) are photographed arriving Friday at a Joint Base Andrews bill signing ceremony

President Trump (left) is seen holding the hand of first lady Melania Trump (right). The couple traveled to Mar-a-Lago for the holidays directly after the signing

First lady Melania Trump (left) introduced President Trump (right) and wished the troops a Merry Christmas and happy and healthy new year

First lady Melania Trump, Vice President Mike Pence, second lady Karen Pence and first daugher Ivanka Trump sit row at Friday's bill signing

First daughter and White House adviser Ivanka Trump is seen awaiting her father at a defense bill signing ceremony Friday at Joint Base Andrews

Barron Trump (left) accompanies his parents first lady Melania Trump (center) and President Trump (right) as they board Air Force One to head to Florida for the holidays

It's unclear what Space Force's uniform, logo and other hallmarks will look like as Trump signed Space Force into being before the military had a chance to finalize those details.

'It's going to be really important that we get this right. A uniform, a patch, a song, it gets to the culture of a service and so we're not going to be in a rush to get something and not do that right,' Raymond said, adding that 'I don't think it's going to take a long time to get that done, but that's not something that we're going to roll out on day one.'

While signing the 2020 National Defense Authorization Act Friday night, Trump marveled at the size of the spending package, noting that it was billions - 'that's with a B.'

'That's an all-time record in the history of our country,' he told the crowd of troops gathered. 'What's the good of a budget if you don't have the best military in the world.'

Of that amount, only $40million was allocated to the Space Force during the 2020 Fiscal Year - less than $72.4million that the Pentagon had been hoping for.

Space Force 'will phase development according to what the budget provides. Yes, it was less than requested, but we will quite ably work with the amount that was appropriated,' Barrett said, according to CNN.

The National Defense Authorization Act also created a senior Space Force military post who will oversee the new branch of the Armed Forces and sit on the Joint Chiefs of Staff.

Gen. Raymond (left) is now commander of US Space Command and Air Force Space Command. Air Force Secretary Barbara Barrett (right) now also oversees the Space Force

The military has not yet determined what the Space Force uniform or logo will look like, but the US Space Command flag (pictured) was previously revealed in August 2019

On Friday, Trump announced that Gen. Raymond would be 'The first chief of Space Operations, and he will become the very first member of the Space Force and he will be on the Joint Chiefs, he will be on the Joint Chiefs, which are now expanding by one position that's a very powerful position.

'So General Raymond, congratulations and thank you for everything,' Trump added.

During the bill signing, Trump remarked that it had been 70 years since a branch of the military had been created - the last being the Air Force under President Harry Truman in 1947,

'Think of that, we will create a brand new American military service - that's such a momentous statement,' Trump said.

'It's a big moment,' he went on. 'That's a big moment and we're all here for it.'

'Space. There's going to be a lot of things happening in space. Because space is the world's newest war-fighting domain,' he added.

Trump said he believed there could be 'grave threats to our national security' coming from space.

'American superiority in space is absolutely vital - we're leading, but we're not leading by enough, but very shortly we'll be leading by alot,' he said.

First lady Melania Trump, daughter Ivanka Trump and son-in-law Jared Kushner were with him when he put pen to paper.

The first lady introduced her husband.

'On behalf of my family I want to thank every member of our military and their families for their devotion to our country and their courage to defend our freedoms,' she said. 'During this holiday season we send our prayers to all who are serving overseas and who will not be home with their families over Christmas.'

Melania Trump told the service members in the crowd 'our nation is with you.'

'Wishing you a all a very merry Christmas and a happy and healthy new year,' she said, before turning over the podium to her husband.

The bill contains several measure Ivanka Trump lobbied lawmakers for, including an increase to the nation’s largest federal child care assistance program by half a billion dollars; some $250 million for historically black universities; paid family and medical leave for federal employees; and $100 million for USAID's Women's Global Development and Prosperity (W-GDP) Fund.

Earlier in the day Trump took to Twitter to tout the legislation's provisions, such as its 3.1 per cent military pay raise, paid leave for federal workers – and an increase in the 'smocking age.'

That provision, inserted by congressional negotiators, would raise the age for all tobacco purchases to 21. Some military members have complained that they can fight for the nation at age 18 but not buy tobacco products until later.

Trump corrected the spelling of his tweet after blasting it out, but not before being chided by critics including George Conway, the husband of counselor to the president Kellyanne Conway.

President Donald Trump will sign a $738 billion defense bill before heading to Mar-a-Lago Friday night

President Trump touted the massive $738 billion defense bill he will sign, and said it would raise the 'smocking age' to 21

CLEAN UP DUTY: The president then put out a tweet with the corrected spelling

'I will be signing our 738 Billion Dollar Defense Spending Bill today. It will include 12 weeks Paid Parental Leave, gives our troops a raise, importantly creates the SPACE FORCE, SOUTHERN BORDER WALL FUNDING, repeals “Cadillac Tax” on Health Plans, raises smocking age to 21! BIG!' Trump tweeted early Friday.

The spelling error was enough to set off Conway, who tweeted: 'I agree with IMPOTUS @realDonaldTrump that people should not smock until age 21. #IMPOTUS,' touting his own pro-impeachment stance for the president, who is sometimes referred to as POTUS.

The bill provides a $22 billion increase in defense funding, while establishing the new 'Space Force' that Trump wanted. The head of that agency will report to the head of the Air Force but also serve among the Joint Chiefs of Staff.

The 3,488-page bill provides does not contain a prohibition on border wall funding. Republicans pushed to allow the administration to continue to be able to raid funds appropriated for other things as part of Trump's gambit to secure 'emergency' wall construction, but it was not included in a final deal.

The spending measure includes $1.4 billion for wall construction, the same as last year and short of the original Administration request for $8.6 billion – although without the restrictions on raiding other funds.

The massive bill includes 3.1 per cent pay raise for military members

The bill Trump signed Friday also raises the smoking age to 21

Funding for border barriers is flat, but negotiators dropped Democratic provisions that would prevent the administration from raiding funds from other areas

Trump was expected to sign the bill before heading to Mar-a-Lago for the holidays

The compromise easily passed the House and Senate, although a faction of progressive lawmakers including Rep. Ro Khanna of California and Sen. Bernie Sanders blasted it.

"There is no pressing reason for Congress to shower Trump, his Saudi friends, and the Pentagon contractors of the military-industrial complex with this $738-billion taxpayer giveaway right now,' Sander said in a statement when negotiators reached a deal earlier this month. 'We owe it to the American people to go back to the drawing board. Congress must say no,' he said.

Senate Armed Services Committee Chairman James Inhofe of Oklahoma called the space force 'the president’s big deal,” saying he had 'some reluctance at first' in backing it, The Hill reported.

“It will help protect space and ensure America’s dominance in this warfighting domain for years to come,” Inhofe said. “China and Russia have their own space dominance ... and just the fact that we don’t have one is something that made people believe we didn’t have an interest in the Space Force.”