Mark Kelly's campaign for Arizona's U.S. Senate seat in 2020 reported raising more than $1.1 million in individual contributions since announcing his candidacy Tuesday.

The retired astronaut and Tucson Democrat launched his campaign for the seat Tuesday morning. By Wednesday evening, his fundraising haul was closing in or eclipsing that of two recent entrants to the 2020 Democratic presidential race.

U.S. Sen. Kamala Harris of California, for example, raised about $1.5 million within 24 hours of announcing she was leaping into the crowded Democratic presidential primary. Sen. Amy Klobuchar raised $1 million over a 48-hour period.

Kelly, 54, touted his financial haul Wednesday morning as it ticked upward.

"A huge thank you to everyone who saw our launch and joined our team yesterday," he wrote on Twitter. "I'm new to this, but I'm told we did well. In the first 24 hours we raised $604K from more than 9,700 contributions. We're #FullSpeedAhead without a DIME of corporate PAC money."

By the end of the day, the number sat at $1.1 million, according to Rodd McLeod, his campaign spokesman.

Democrats across Arizona were lauding his fundraising prowess, but with 18 months to go until the primary election, some potential donors were already jokingly bemoaning the volume of fundraising emails from Kelly's campaign.

Kelly is the first Democrat to jump into the 2020 field. Democratic Rep. Ruben Gallego, of Phoenix, is considering a run.

U.S. Sen. Martha McSally, a Republican, lost to Democrat Kyrsten Sinema in November. Gov. Doug Ducey later appointed McSally to the seat to serve the remainder of the late Sen. John McCain's seat.

A special election is set for 2020; the winner of that race would face re-election in 2022 to serve a full six-year term.

During a Tuesday phone interview with The Arizona Republic from his home in Tucson, Kelly offered a glimpse of the type of campaign he hopes to run. Like Sinema did in 2018, Kelly is casting himself as an almost apolitical figure who can work in a cooperative spirit, even in today's hyper-partisan environment.

Follow the reporter on Twitter. Contact her at yvonne.wingett@arizonarepublic.com.